Commit Graph

5472 Commits

Author SHA1 Message Date
Yazen Ghannam
5176a93ab2 x86/MCE/AMD, EDAC/mce_amd: Add new SMCA bank types
Add HWID and McaType values for new SMCA bank types, and add their error
descriptions to edac_mce_amd.

The "PHY" bank types all have the same error descriptions, and the NBIF
and SHUB bank types have the same error descriptions. So reuse the same
arrays where appropriate.

  [ bp: Remove useless comments over hwid types. ]

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211216162905.4132657-2-yazen.ghannam@amd.com
2021-12-22 17:19:18 +01:00
Borislav Petkov
b64dfcde1c x86/mm: Prevent early boot triple-faults with instrumentation
Commit in Fixes added a global TLB flush on the early boot path, after
the kernel switches off of the trampoline page table.

Compiler profiling options enabled with GCOV_PROFILE add additional
measurement code on clang which needs to be initialized prior to
use. The global flush in x86_64_start_kernel() happens before those
initializations can happen, leading to accessing invalid memory.
GCOV_PROFILE builds with gcc are still ok so this is clang-specific.

The second issue this fixes is with KASAN: for a similar reason,
kasan_early_init() needs to have happened before KASAN-instrumented
functions are called.

Therefore, reorder the flush to happen after the KASAN early init
and prevent the compilers from adding profiling instrumentation to
native_write_cr4().

Fixes: f154f29085 ("x86/mm/64: Flush global TLB on boot and AP bringup")
Reported-by: "J. Bruce Fields" <bfields@fieldses.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Carel Si <beibei.si@intel.com>
Tested-by: "J. Bruce Fields" <bfields@fieldses.org>
Link: https://lore.kernel.org/r/20211209144141.GC25654@xsang-OptiPlex-9020
2021-12-22 11:51:20 +01:00
Tianyu Lan
062a5c4260 hyper-v: Enable swiotlb bounce buffer for Isolation VM
hyperv Isolation VM requires bounce buffer support to copy
data from/to encrypted memory and so enable swiotlb force
mode to use swiotlb bounce buffer for DMA transaction.

In Isolation VM with AMD SEV, the bounce buffer needs to be
accessed via extra address space which is above shared_gpa_boundary
(E.G 39 bit address line) reported by Hyper-V CPUID ISOLATION_CONFIG.
The access physical address will be original physical address +
shared_gpa_boundary. The shared_gpa_boundary in the AMD SEV SNP
spec is called virtual top of memory(vTOM). Memory addresses below
vTOM are automatically treated as private while memory above
vTOM is treated as shared.

Swiotlb bounce buffer code calls set_memory_decrypted()
to mark bounce buffer visible to host and map it in extra
address space via memremap. Populate the shared_gpa_boundary
(vTOM) via swiotlb_unencrypted_base variable.

The map function memremap() can't work in the early place
(e.g ms_hyperv_init_platform()) and so call swiotlb_update_mem_
attributes() in the hyperv_init().

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20211213071407.314309-4-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-12-20 18:01:09 +00:00
Borislav Petkov
1acd85feba x86/mce: Check regs before accessing it
Commit in Fixes accesses pt_regs before checking whether it is NULL or
not. Make sure the NULL pointer check happens first.

Fixes: 0a5b288e85 ("x86/mce: Prevent severity computation from being instrumented")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20211217102029.GA29708@kili
2021-12-20 11:41:02 +01:00
Borislav Petkov
e3d72e8eee x86/mce: Mark mce_start() noinstr
Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0x4ae: call to __const_udelay() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-13-bp@alien8.de
2021-12-13 14:14:05 +01:00
Borislav Petkov
edb3d07e24 x86/mce: Mark mce_timed_out() noinstr
Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0x482: call to mce_timed_out() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-12-bp@alien8.de
2021-12-13 14:13:54 +01:00
Borislav Petkov
75581a203e x86/mce: Move the tainting outside of the noinstr region
add_taint() is yet another external facility which the #MC handler
calls. Move that tainting call into the instrumentation-allowed part of
the handler.

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0x617: call to add_taint() leaves .noinstr.text section

While at it, allow instrumentation around the mce_log() call.

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0x690: call to mce_log() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-11-bp@alien8.de
2021-12-13 14:13:35 +01:00
Borislav Petkov
db6c996d6c x86/mce: Mark mce_read_aux() noinstr
Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0x681: call to mce_read_aux() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-10-bp@alien8.de
2021-12-13 14:13:23 +01:00
Borislav Petkov
b4813539d3 x86/mce: Mark mce_end() noinstr
It is called by the #MC handler which is noinstr.

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xbd6: call to memset() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-9-bp@alien8.de
2021-12-13 14:13:12 +01:00
Borislav Petkov
3c7ce80a81 x86/mce: Mark mce_panic() noinstr
And allow instrumentation inside it because it does calls to other
facilities which will not be tagged noinstr.

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xc73: call to mce_panic() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-8-bp@alien8.de
2021-12-13 14:13:01 +01:00
Borislav Petkov
0a5b288e85 x86/mce: Prevent severity computation from being instrumented
Mark all the MCE severity computation logic noinstr and allow
instrumentation when it "calls out".

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xc5d: call to mce_severity() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-7-bp@alien8.de
2021-12-13 14:12:48 +01:00
Borislav Petkov
4fbce464db x86/mce: Allow instrumentation during task work queueing
Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xdb1: call to queue_task_work() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-6-bp@alien8.de
2021-12-13 14:12:35 +01:00
Borislav Petkov
487d654db3 x86/mce: Remove noinstr annotation from mce_setup()
Instead, sandwitch around the call which is done in noinstr context and
mark the caller - mce_gather_info() - as noinstr.

Also, document what the whole instrumentation strategy with #MC is going
to be in the future and where it all is supposed to be going to.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-5-bp@alien8.de
2021-12-13 14:12:21 +01:00
Borislav Petkov
88f66a4235 x86/mce: Use mce_rdmsrl() in severity checking code
MCA has its own special MSR accessors. Use them.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-4-bp@alien8.de
2021-12-13 14:12:08 +01:00
Borislav Petkov
ad669ec16a x86/mce: Remove function-local cpus variables
Use num_online_cpus() directly.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-3-bp@alien8.de
2021-12-13 14:11:53 +01:00
Borislav Petkov
cd5e0d1fc9 x86/mce: Do not use memset to clear the banks bitmaps
The bitmap is a single unsigned long so no need for the function call.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-2-bp@alien8.de
2021-12-13 14:11:22 +01:00
Peter Zijlstra
5ce8e39f55 x86/sgx: Remove .fixup usage
Create EX_TYPE_FAULT_SGX which does as EX_TYPE_FAULT does, except adds
this extra bit that SGX really fancies having.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.961246679@infradead.org
2021-12-11 09:09:49 +01:00
Colin Ian King
df0114f1f8 x86/resctrl: Remove redundant assignment to variable chunks
The variable chunks is being shifted right and re-assinged the shifted
value which is then returned. Since chunks is not being read afterwards
the assignment is redundant and the >>= operator can be replaced with a
shift >> operator instead.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lkml.kernel.org/r/20211207223735.35173-1-colin.i.king@gmail.com
2021-12-09 09:57:16 -08:00
Jarkko Sakkinen
50468e4313 x86/sgx: Add an attribute for the amount of SGX memory in a NUMA node
== Problem ==

The amount of SGX memory on a system is determined by the BIOS and it
varies wildly between systems.  It can be as small as dozens of MB's
and as large as many GB's on servers.  Just like how applications need
to know how much regular RAM is available, enclave builders need to
know how much SGX memory an enclave can consume.

== Solution ==

Introduce a new sysfs file:

	/sys/devices/system/node/nodeX/x86/sgx_total_bytes

to enumerate the amount of SGX memory available in each NUMA node.
This serves the same function for SGX as /proc/meminfo or
/sys/devices/system/node/nodeX/meminfo does for normal RAM.

'sgx_total_bytes' is needed today to help drive the SGX selftests.
SGX-specific swap code is exercised by creating overcommitted enclaves
which are larger than the physical SGX memory on the system.  They
currently use a CPUID-based approach which can diverge from the actual
amount of SGX memory available.  'sgx_total_bytes' ensures that the
selftests can work efficiently and do not attempt stupid things like
creating a 100,000 MB enclave on a system with 128 MB of SGX memory.

== Implementation Details ==

Introduce CONFIG_HAVE_ARCH_NODE_DEV_GROUP opt-in flag to expose an
arch specific attribute group, and add an attribute for the amount of
SGX memory in bytes to each NUMA node:

== ABI Design Discussion ==

As opposed to the per-node ABI, a single, global ABI was considered.
However, this would prevent enclaves from being able to size
themselves so that they fit on a single NUMA node.  Essentially, a
single value would rule out NUMA optimizations for enclaves.

Create a new "x86/" directory inside each "nodeX/" sysfs directory.
'sgx_total_bytes' is expected to be the first of at least a few
sgx-specific files to be placed in the new directory.  Just scanning
/proc/meminfo, these are the no-brainers that we have for RAM, but we
need for SGX:

	MemTotal:       xxxx kB // sgx_total_bytes (implemented here)
	MemFree:        yyyy kB // sgx_free_bytes
	SwapTotal:      zzzz kB // sgx_swapped_bytes

So, at *least* three.  I think we will eventually end up needing
something more along the lines of a dozen.  A new directory (as
opposed to being in the nodeX/ "root") directory avoids cluttering the
root with several "sgx_*" files.

Place the new file in a new "nodeX/x86/" directory because SGX is
highly x86-specific.  It is very unlikely that any other architecture
(or even non-Intel x86 vendor) will ever implement SGX.  Using "sgx/"
as opposed to "x86/" was also considered.  But, there is a real chance
this can get used for other arch-specific purposes.

[ dhansen: rewrite changelog ]

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211116162116.93081-2-jarkko@kernel.org
2021-12-09 07:02:22 -08:00
Smita Koralahalli
1e56279a49 x86/mce/inject: Set the valid bit in MCA_STATUS before error injection
MCA handlers check the valid bit in each status register
(MCA_STATUS[Val]) and continue processing the error only if the valid
bit is set.

Set the valid bit unconditionally in the corresponding MCA_STATUS
register and correct any Val=0 injections made by the user as such
errors will get ignored and such injections will be largely pointless.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211104215846.254012-3-Smita.KoralahalliChannabasappa@amd.com
2021-12-08 12:01:01 +01:00
Smita Koralahalli
e48d008bd1 x86/mce/inject: Check if a bank is populated before injecting
The MCA_IPID register uniquely identifies a bank's type on Scalable MCA
(SMCA) systems. When an MCA bank is not populated, the MCA_IPID register
will read as zero and writes to it will be ignored.

On a hw-type error injection (injection which writes the actual MCA
registers in an attempt to cause a real MCE) check the value of this
register before trying to inject the error.

Do not impose any limitations on a sw injection and allow the user to
test out all the decoding paths without relying on the available hardware,
as its purpose is to just test the code.

 [ bp: Heavily massage. ]

Link: https://lkml.kernel.org/r/20211019233641.140275-2-Smita.KoralahalliChannabasappa@amd.com
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211104215846.254012-2-Smita.KoralahalliChannabasappa@amd.com
2021-12-08 12:00:56 +01:00
Andi Kleen
9c7e2634f6 x86/cpu: Don't write CSTAR MSR on Intel CPUs
Intel CPUs do not support SYSCALL in 32-bit mode, but the kernel
initializes MSR_CSTAR unconditionally. That MSR write is normally
ignored by the CPU, but in a TDX guest it raises a #VE trap.

Exclude Intel CPUs from the MSR_CSTAR initialization.

[ tglx: Fixed the subject line and removed the redundant comment. ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20211119035803.4012145-1-sathyanarayanan.kuppuswamy@linux.intel.com
2021-11-25 00:40:34 +01:00
Linus Torvalds
40c93d7fff Merge tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:

 - Move the command line preparation and the early command line parsing
   earlier so that the command line parameters which affect
   early_reserve_memory(), e.g. efi=nosftreserve, are taken into
   account. This was broken when the invocation of
   early_reserve_memory() was moved recently.

 - Use an atomic type for the SGX page accounting, which is read and
   written locklessly, to plug various race conditions related to it.

* tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sgx: Fix free page accounting
  x86/boot: Pull up cmdline preparation and early param parsing
2021-11-21 11:25:19 -08:00
Ingo Molnar
5c16f7ee03 Merge branch 'x86/urgent' into x86/sgx, to resolve conflict
Conflicts:
	arch/x86/kernel/cpu/sgx/main.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-11-19 09:31:55 +01:00
Zhaolong Zhang
2322b532ad x86/mce: Get rid of cpu_missing
Get rid of cpu_missing because

  7bb39313cd ("x86/mce: Make mce_timed_out() identify holdout CPUs")

provides a more detailed message about which CPUs are missing.

Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Zhaolong Zhang <zhangzl2013@126.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211109112345.2673403-1-zhangzl2013@126.com
2021-11-17 15:32:31 +01:00
Reinette Chatre
ac5d272a0a x86/sgx: Fix free page accounting
The SGX driver maintains a single global free page counter,
sgx_nr_free_pages, that reflects the number of free pages available
across all NUMA nodes. Correspondingly, a list of free pages is
associated with each NUMA node and sgx_nr_free_pages is updated
every time a page is added or removed from any of the free page
lists. The main usage of sgx_nr_free_pages is by the reclaimer
that runs when it (sgx_nr_free_pages) goes below a watermark
to ensure that there are always some free pages available to, for
example, support efficient page faults.

With sgx_nr_free_pages accessed and modified from a few places
it is essential to ensure that these accesses are done safely but
this is not the case. sgx_nr_free_pages is read without any
protection and updated with inconsistent protection by any one
of the spin locks associated with the individual NUMA nodes.
For example:

      CPU_A                                 CPU_B
      -----                                 -----
 spin_lock(&nodeA->lock);              spin_lock(&nodeB->lock);
 ...                                   ...
 sgx_nr_free_pages--;  /* NOT SAFE */  sgx_nr_free_pages--;

 spin_unlock(&nodeA->lock);            spin_unlock(&nodeB->lock);

Since sgx_nr_free_pages may be protected by different spin locks
while being modified from different CPUs, the following scenario
is possible:

      CPU_A                                CPU_B
      -----                                -----
{sgx_nr_free_pages = 100}
 spin_lock(&nodeA->lock);              spin_lock(&nodeB->lock);
 sgx_nr_free_pages--;                  sgx_nr_free_pages--;
 /* LOAD sgx_nr_free_pages = 100 */    /* LOAD sgx_nr_free_pages = 100 */
 /* sgx_nr_free_pages--          */    /* sgx_nr_free_pages--          */
 /* STORE sgx_nr_free_pages = 99 */    /* STORE sgx_nr_free_pages = 99 */
 spin_unlock(&nodeA->lock);            spin_unlock(&nodeB->lock);

In the above scenario, sgx_nr_free_pages is decremented from two CPUs
but instead of sgx_nr_free_pages ending with a value that is two less
than it started with, it was only decremented by one while the number
of free pages were actually reduced by two. The consequence of
sgx_nr_free_pages not being protected is that its value may not
accurately reflect the actual number of free pages on the system,
impacting the availability of free pages in support of many flows.

The problematic scenario is when the reclaimer does not run because it
believes there to be sufficient free pages while any attempt to allocate
a page fails because there are no free pages available. In the SGX driver
the reclaimer's watermark is only 32 pages so after encountering the
above example scenario 32 times a user space hang is possible when there
are no more free pages because of repeated page faults caused by no
free pages made available.

The following flow was encountered:
asm_exc_page_fault
 ...
   sgx_vma_fault()
     sgx_encl_load_page()
       sgx_encl_eldu() // Encrypted page needs to be loaded from backing
                       // storage into newly allocated SGX memory page
         sgx_alloc_epc_page() // Allocate a page of SGX memory
           __sgx_alloc_epc_page() // Fails, no free SGX memory
           ...
           if (sgx_should_reclaim(SGX_NR_LOW_PAGES)) // Wake reclaimer
             wake_up(&ksgxd_waitq);
           return -EBUSY; // Return -EBUSY giving reclaimer time to run
       return -EBUSY;
     return -EBUSY;
   return VM_FAULT_NOPAGE;

The reclaimer is triggered in above flow with the following code:

static bool sgx_should_reclaim(unsigned long watermark)
{
        return sgx_nr_free_pages < watermark &&
               !list_empty(&sgx_active_page_list);
}

In the problematic scenario there were no free pages available yet the
value of sgx_nr_free_pages was above the watermark. The allocation of
SGX memory thus always failed because of a lack of free pages while no
free pages were made available because the reclaimer is never started
because of sgx_nr_free_pages' incorrect value. The consequence was that
user space kept encountering VM_FAULT_NOPAGE that caused the same
address to be accessed repeatedly with the same result.

Change the global free page counter to an atomic type that
ensures simultaneous updates are done safely. While doing so, move
the updating of the variable outside of the spin lock critical
section to which it does not belong.

Cc: stable@vger.kernel.org
Fixes: 901ddbb9ec ("x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page()")
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/a95a40743bbd3f795b465f30922dde7f1ea9e0eb.1637004094.git.reinette.chatre@intel.com
2021-11-16 11:17:43 -08:00
Tony Luck
a495cbdffa x86/sgx: Add SGX infrastructure to recover from poison
Provide a recovery function sgx_memory_failure(). If the poison was
consumed synchronously then send a SIGBUS. Note that the virtual
address of the access is not included with the SIGBUS as is the case
for poison outside of SGX enclaves. This doesn't matter as addresses
of code/data inside an enclave is of little to no use to code executing
outside the (now dead) enclave.

Poison found in a free page results in the page being moved from the
free list to the per-node poison page list.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-5-tony.luck@intel.com
2021-11-15 11:13:16 -08:00
Tony Luck
992801ae92 x86/sgx: Initial poison handling for dirty and free pages
A memory controller patrol scrubber can report poison in a page
that isn't currently being used.

Add "poison" field in the sgx_epc_page that can be set for an
sgx_epc_page. Check for it:
1) When sanitizing dirty pages
2) When freeing epc pages

Poison is a new field separated from flags to avoid having to make all
updates to flags atomic, or integrate poison state changes into some
other locking scheme to protect flags (Currently just sgx_reclaimer_lock
which protects the SGX_EPC_PAGE_RECLAIMER_TRACKED bit in page->flags).

In both cases place the poisoned page on a per-node list of poisoned
epc pages to make sure it will not be reallocated.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-4-tony.luck@intel.com
2021-11-15 11:13:16 -08:00
Tony Luck
40e0e7843e x86/sgx: Add infrastructure to identify SGX EPC pages
X86 machine check architecture reports a physical address when there
is a memory error. Handling that error requires a method to determine
whether the physical address reported is in any of the areas reserved
for EPC pages by BIOS.

SGX EPC pages do not have Linux "struct page" associated with them.

Keep track of the mapping from ranges of EPC pages to the sections
that contain them using an xarray. N.B. adds CONFIG_XARRAY_MULTI to
the SGX dependecies. So "select" that in arch/x86/Kconfig for X86/SGX.

Create a function arch_is_platform_page() that simply reports whether an
address is an EPC page for use elsewhere in the kernel. The ACPI error
injection code needs this function and is typically built as a module,
so export it.

Note that arch_is_platform_page() will be slower than other similar
"what type is this page" functions that can simply check bits in the
"struct page".  If there is some future performance critical user of
this function it may need to be implemented in a more efficient way.

Note also that the current implementation of xarray allocates a few
hundred kilobytes for this usage on a system with 4GB of SGX EPC memory
configured. This isn't ideal, but worth it for the code simplicity.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-3-tony.luck@intel.com
2021-11-15 11:13:16 -08:00
Tony Luck
d6d261bded x86/sgx: Add new sgx_epc_page flag bit to mark free pages
SGX EPC pages go through the following life cycle:

        DIRTY ---> FREE ---> IN-USE --\
                    ^                 |
                    \-----------------/

Recovery action for poison for a DIRTY or FREE page is simple. Just
make sure never to allocate the page. IN-USE pages need some extra
handling.

Add a new flag bit SGX_EPC_PAGE_IS_FREE that is set when a page
is added to a free list and cleared when the page is allocated.

Notes:

1) These transitions are made while holding the node->lock so that
   future code that checks the flags while holding the node->lock
   can be sure that if the SGX_EPC_PAGE_IS_FREE bit is set, then the
   page is on the free list.

2) Initially while the pages are on the dirty list the
   SGX_EPC_PAGE_IS_FREE bit is cleared.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-2-tony.luck@intel.com
2021-11-15 11:13:16 -08:00
Sean Christopherson
f3e613e72f x86/hyperv: Move required MSRs check to initial platform probing
Explicitly check for MSR_HYPERCALL and MSR_VP_INDEX support when probing
for running as a Hyper-V guest instead of waiting until hyperv_init() to
detect the bogus configuration.  Add messages to give the admin a heads
up that they are likely running on a broken virtual machine setup.

At best, silently disabling Hyper-V is confusing and difficult to debug,
e.g. the kernel _says_ it's using all these fancy Hyper-V features, but
always falls back to the native versions.  At worst, the half baked setup
will crash/hang the kernel.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20211104182239.1302956-3-seanjc@google.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-11-15 12:37:08 +00:00
Yazen Ghannam
0b746e8c1e x86/MCE/AMD, EDAC/amd64: Move address translation to AMD64 EDAC
The address translation code used for current AMD systems is
non-architectural. So move it to EDAC.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211028175728.121452-2-yazen.ghannam@amd.com
2021-11-15 12:36:32 +01:00
Linus Torvalds
1654e95ee3 Merge tag 'x86_urgent_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:

 - Add the model number of a new, Raptor Lake CPU, to intel-family.h

 - Do not log spurious corrected MCEs on SKL too, due to an erratum

 - Clarify the path of paravirt ops patches upstream

 - Add an optimization to avoid writing out AMX components to sigframes
   when former are in init state

* tag 'x86_urgent_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Add Raptor Lake to Intel family
  x86/mce: Add errata workaround for Skylake SKX37
  MAINTAINERS: Add some information to PARAVIRT_OPS entry
  x86/fpu: Optimize out sigframe xfeatures when in init state
2021-11-14 09:29:03 -08:00
Dave Jones
e629fc1407 x86/mce: Add errata workaround for Skylake SKX37
Errata SKX37 is word-for-word identical to the other errata listed in
this workaround.   I happened to notice this after investigating a CMCI
storm on a Skylake host.  While I can't confirm this was the root cause,
spurious corrected errors does sound like a likely suspect.

Fixes: 2976908e41 ("x86/mce: Do not log spurious corrected mce errors")
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20211029205759.GA7385@codemonkey.org.uk
2021-11-12 11:43:35 -08:00
Linus Torvalds
95faf6ba65 Merge tag 'driver-core-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
 "Here is the big set of driver core changes for 5.16-rc1.

  All of these have been in linux-next for a while now with no reported
  problems.

  Included in here are:

   - big update and cleanup of the sysfs abi documentation files and
     scripts from Mauro. We are almost at the place where we can
     properly check that the running kernel's sysfs abi is documented
     fully.

   - firmware loader updates

   - dyndbg updates

   - kernfs cleanups and fixes from Christoph

   - device property updates

   - component fix

   - other minor driver core cleanups and fixes"

* tag 'driver-core-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (122 commits)
  device property: Drop redundant NULL checks
  x86/build: Tuck away built-in firmware under FW_LOADER
  vmlinux.lds.h: wrap built-in firmware support under FW_LOADER
  firmware_loader: move struct builtin_fw to the only place used
  x86/microcode: Use the firmware_loader built-in API
  firmware_loader: remove old DECLARE_BUILTIN_FIRMWARE()
  firmware_loader: formalize built-in firmware API
  component: do not leave master devres group open after bind
  dyndbg: refine verbosity 1-4 summary-detail
  gpiolib: acpi: Replace custom code with device_match_acpi_handle()
  i2c: acpi: Replace custom function with device_match_acpi_handle()
  driver core: Provide device_match_acpi_handle() helper
  dyndbg: fix spurious vNpr_info change
  dyndbg: no vpr-info on empty queries
  dyndbg: vpr-info on remove-module complete, not starting
  device property: Add missed header in fwnode.h
  Documentation: dyndbg: Improve cli param examples
  dyndbg: Remove support for ddebug_query param
  dyndbg: make dyndbg a known cli param
  dyndbg: show module in vpr-info in dd-exec-queries
  ...
2021-11-04 08:32:38 -07:00
Dave Hansen
30d02551ba x86/fpu: Optimize out sigframe xfeatures when in init state
tl;dr: AMX state is ~8k.  Signal frames can have space for this
~8k and each signal entry writes out all 8k even if it is zeros.
Skip writing zeros for AMX to speed up signal delivery by about
4% overall when AMX is in its init state.

This is a user-visible change to the sigframe ABI.

== Hardware XSAVE Background ==

XSAVE state components may be tracked by the processor as being
in their initial configuration.  Software can detect which
features are in this configuration by looking at the XSTATE_BV
field in an XSAVE buffer or with the XGETBV(1) instruction.

Both the XSAVE and XSAVEOPT instructions enumerate features s
being in the initial configuration via the XSTATE_BV field in the
XSAVE header,  However, XSAVEOPT declines to actually write
features in their initial configuration to the buffer.  XSAVE
writes the feature unconditionally, regardless of whether it is
in the initial configuration or not.

Basically, XSAVE users never need to inspect XSTATE_BV to
determine if the feature has been written to the buffer.
XSAVEOPT users *do* need to inspect XSTATE_BV.  They might also
need to clear out the buffer if they want to make an isolated
change to the state, like modifying one register.

== Software Signal / XSAVE Background ==

Signal frames have historically been written with XSAVE itself.
Each state is written in its entirety, regardless of being in its
initial configuration.

In other words, the signal frame ABI uses the XSAVE behavior, not
the XSAVEOPT behavior.

== Problem ==

This means that any application which has acquired permission to
use AMX via ARCH_REQ_XCOMP_PERM will write 8k of state to the
signal frame.  This 8k write will occur even when AMX was in its
initial configuration and software *knows* this because of
XSTATE_BV.

This problem also exists to a lesser degree with AVX-512 and its
2k of state.  However, AVX-512 use does not require
ARCH_REQ_XCOMP_PERM and is more likely to have existing users
which would be impacted by any change in behavior.

== Solution ==

Stop writing out AMX xfeatures which are in their initial state
to the signal frame.  This effectively makes the signal frame
XSAVE buffer look as if it were written with a combination of
XSAVEOPT and XSAVE behavior.  Userspace which handles XSAVEOPT-
style buffers should be able to handle this naturally.

For now, include only the AMX xfeatures: XTILE and XTILEDATA in
this new behavior.  These require new ABI to use anyway, which
makes their users very unlikely to be broken.  This XSAVEOPT-like
behavior should be expected for all future dynamic xfeatures.  It
may also be extended to legacy features like AVX-512 in the
future.

Only attempt this optimization on systems with dynamic features.
Disable dynamic feature support (XFD) if XGETBV1 is unavailable
by adding a CPUID dependency.

This has been measured to reduce the *overall* cycle cost of
signal delivery by about 4%.

Fixes: 2308ee57d9 ("x86/fpu/amx: Enable the AMX feature in 64-bit mode")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: "Chang S. Bae" <chang.seok.bae@intel.com>
Link: https://lore.kernel.org/r/20211102224750.FA412E26@davehans-spike.ostc.intel.com
2021-11-03 22:42:35 +01:00
Linus Torvalds
56d3375448 Merge tag 'drm-next-2021-11-03' of git://anongit.freedesktop.org/drm/drm
Pull drm updates from Dave Airlie:
 "Summary below. i915 starts to add support for DG2 GPUs, enables DG1
  and ADL-S support by default, lots of work to enable DisplayPort 2.0
  across drivers. Lots of documentation updates and fixes across the
  board.

  core:
   - improve dma_fence, lease and resv documentation
   - shmem-helpers: allocate WC pages on x86, use vmf_insert_pin
   - sched fixes/improvements
   - allow empty drm leases
   - add dma resv iterator
   - add more DP 2.0 headers
   - DP MST helper improvements for DP2.0

  dma-buf:
   - avoid warnings, remove fence trace macros

  bridge:
   - new helper to get rid of panels
   - probe improvements for it66121
   - enable DSI EOTP for anx7625

  fbdev:
   - efifb: release runtime PM on destroy

  ttm:
   - kerneldoc switch
   - helper to clear all DMA mappings
   - pool shrinker optimizaton
   - remove ttm_tt_destroy_common
   - update ttm_move_memcpy for async use

  panel:
   - add new panel-edp driver

  amdgpu:
   - Initial DP 2.0 support
   - Initial USB4 DP tunnelling support
   - Aldebaran MCE support
   - Modifier support for DCC image stores for GFX 10.3
   - Display rework for better FP code handling
   - Yellow Carp/Cyan Skillfish updates
   - Cyan Skillfish display support
   - convert vega/navi to IP discovery asic enumeration
   - validate IP discovery table
   - RAS improvements
   - Lots of fixes

  i915:
   - DG1 PCI IDs + LMEM discovery/placement
   - DG1 GuC submission by default
   - ADL-S PCI IDs updated + enabled by default
   - ADL-P (XE_LPD) fixed and updates
   - DG2 display fixes
   - PXP protected object support for Gen12 integrated
   - expose multi-LRC submission interface for GuC
   - export logical engine instance to user
   - Disable engine bonding on Gen12+
   - PSR cleanup
   - PSR2 selective fetch by default
   - DP 2.0 prep work
   - VESA vendor block + MSO use of it
   - FBC refactor
   - try again to fix fast-narrow vs slow-wide eDP training
   - use THP when IOMMU enabled
   - LMEM backup/restore for suspend/resume
   - locking simplification
   - GuC major reworking
   - async flip VT-D workaround changes
   - DP link training improvements
   - misc display refactorings

  bochs:
   - new PCI ID

  rcar-du:
   - Non-contiguious buffer import support for rcar-du
   - r8a779a0 support prep

  omapdrm:
   - COMPILE_TEST fixes

  sti:
   - COMPILE_TEST fixes

  msm:
   - fence ordering improvements
   - eDP support in DP sub-driver
   - dpu irq handling cleanup
   - CRC support for making igt happy
   - NO_CONNECTOR bridge support
   - dsi: 14nm phy support for msm8953
   - mdp5: msm8x53, sdm450, sdm632 support

  stm:
   - layer alpha + zpo support

  v3d:
   - fix Vulkan CTS failure
   - support multiple sync objects

  gud:
   - add R8/RGB332/RGB888 pixel formats

  vc4:
   - convert to new bridge helpers

  vgem:
   - use shmem helpers

  virtio:
   - support mapping exported vram

  zte:
   - remove obsolete driver

  rockchip:
   - use bridge attach no connector for LVDS/RGB"

* tag 'drm-next-2021-11-03' of git://anongit.freedesktop.org/drm/drm: (1259 commits)
  drm/amdgpu/gmc6: fix DMA mask from 44 to 40 bits
  drm/amd/display: MST support for DPIA
  drm/amdgpu: Fix even more out of bound writes from debugfs
  drm/amdgpu/discovery: add SDMA IP instance info for soc15 parts
  drm/amdgpu/discovery: add UVD/VCN IP instance info for soc15 parts
  drm/amdgpu/UAPI: rearrange header to better align related items
  drm/amd/display: Enable dpia in dmub only for DCN31 B0
  drm/amd/display: Fix USB4 hot plug crash issue
  drm/amd/display: Fix deadlock when falling back to v2 from v3
  drm/amd/display: Fallback to clocks which meet requested voltage on DCN31
  drm/amd/display: move FPU associated DCN301 code to DML folder
  drm/amd/display: fix link training regression for 1 or 2 lane
  drm/amd/display: add two lane settings training options
  drm/amd/display: decouple hw_lane_settings from dpcd_lane_settings
  drm/amd/display: implement decide lane settings
  drm/amd/display: adopt DP2.0 LT SCR revision 8
  drm/amd/display: FEC configuration for dpia links in MST mode
  drm/amd/display: FEC configuration for dpia links
  drm/amd/display: Add workaround flag for EDID read on certain docks
  drm/amd/display: Set phy_mux_sel bit in dmub scratch register
  ...
2021-11-02 16:47:49 -07:00
Linus Torvalds
44261f8e28 Merge tag 'hyperv-next-signed-20211102' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv updates from Wei Liu:

 - Initial patch set for Hyper-V isolation VM support (Tianyu Lan)

 - Fix a warning on preemption (Vitaly Kuznetsov)

 - A bunch of misc cleanup patches

* tag 'hyperv-next-signed-20211102' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Protect set_hv_tscchange_cb() against getting preempted
  Drivers: hv : vmbus: Adding NULL pointer check
  x86/hyperv: Remove duplicate include
  x86/hyperv: Remove duplicated include in hv_init
  Drivers: hv: vmbus: Remove unused code to check for subchannels
  Drivers: hv: vmbus: Initialize VMbus ring buffer for Isolation VM
  Drivers: hv: vmbus: Add SNP support for VMbus channel initiate message
  x86/hyperv: Add ghcb hvcall support for SNP VM
  x86/hyperv: Add Write/Read MSR registers via ghcb page
  Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VM
  x86/hyperv: Add new hvcall guest address host visibility support
  x86/hyperv: Initialize shared memory boundary in the Isolation VM.
  x86/hyperv: Initialize GHCB page in Isolation VM
2021-11-02 10:56:49 -07:00
Linus Torvalds
a5a9e00605 Merge tag 'seccomp-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull seccomp updates from Kees Cook:
 "These are x86-specific, but I carried these since they're also
  seccomp-specific.

  This flips the defaults for spec_store_bypass_disable and
  spectre_v2_user from "seccomp" to "prctl", as enough time has passed
  to allow system owners to have updated the defensive stances of their
  various workloads, and it's long overdue to unpessimize seccomp
  threads.

  Extensive rationale and details are in Andrea's main patch.

  Summary:

   - set spec_store_bypass_disable & spectre_v2_user to prctl (Andrea Arcangeli)"

* tag 'seccomp-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  x86: deduplicate the spectre_v2_user documentation
  x86: change default to spec_store_bypass_disable=prctl spectre_v2_user=prctl
2021-11-01 17:25:09 -07:00
Linus Torvalds
879dbe9ffe Merge tag 'x86_sgx_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SGX updates from Borislav Petkov:
 "Add a SGX_IOC_VEPC_REMOVE ioctl to the /dev/sgx_vepc virt interface
  with which EPC pages can be put back into their uninitialized state
  without having to reopen /dev/sgx_vepc, which could not be possible
  anymore after startup due to security policies"

* tag 'x86_sgx_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sgx/virt: implement SGX_IOC_VEPC_REMOVE ioctl
  x86/sgx/virt: extract sgx_vepc_remove_page
2021-11-01 15:54:07 -07:00
Linus Torvalds
e0f4c59dc4 Merge tag 'x86_cpu_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Borislav Petkov:

 - Start checking a CPUID bit on AMD Zen3 which states that the CPU
   clears the segment base when a null selector is written. Do the
   explicit detection on older CPUs, zen2 and hygon specifically, which
   have the functionality but do not advertize the CPUID bit. Factor in
   the presence of a hypervisor underneath the kernel and avoid doing
   the explicit check there which the HV might've decided to not
   advertize for migration safety reasons, or similar.

 - Add support for a new X86 CPU vendor: VORTEX. Needed for whitelisting
   those CPUs in the hardware vulnerabilities detection

 - Force the compiler to use rIP-relative addressing in the fallback
   path of static_cpu_has(), in order to avoid unnecessary register
   pressure

* tag 'x86_cpu_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Fix migration safety with X86_BUG_NULL_SEL
  x86/CPU: Add support for Vortex CPUs
  x86/umip: Downgrade warning messages to debug loglevel
  x86/asm: Avoid adding register pressure for the init case in static_cpu_has()
  x86/asm: Add _ASM_RIP() macro for x86-64 (%rip) suffix
2021-11-01 15:33:54 -07:00
Linus Torvalds
158405e888 Merge tag 'ras_core_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RAS updates from Borislav Petkov:

 - Get rid of a bunch of function pointers used in MCA land in favor of
   normal functions. This is in preparation of making the MCA code
   noinstr-aware

 - When the kernel copies data from user addresses and it encounters a
   machine check, a SIGBUS is sent to that process. Change this action
   to either an -EFAULT which is returned to the user or a short write,
   making the recovery action a lot more user-friendly

* tag 'ras_core_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Sort mca_config members to get rid of unnecessary padding
  x86/mce: Get rid of the ->quirk_no_way_out() indirect call
  x86/mce: Get rid of msr_ops
  x86/mce: Get rid of machine_check_vector
  x86/mce: Get rid of the mce_severity function pointer
  x86/mce: Drop copyin special case for #MC
  x86/mce: Change to not send SIGBUS error during copy from user
2021-11-01 15:12:04 -07:00
Linus Torvalds
8cb1ae19bf Merge tag 'x86-fpu-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fpu updates from Thomas Gleixner:

 - Cleanup of extable fixup handling to be more robust, which in turn
   allows to make the FPU exception fixups more robust as well.

 - Change the return code for signal frame related failures from
   explicit error codes to a boolean fail/success as that's all what the
   calling code evaluates.

 - A large refactoring of the FPU code to prepare for adding AMX
   support:

      - Distangle the public header maze and remove especially the
        misnomed kitchen sink internal.h which is despite it's name
        included all over the place.

      - Add a proper abstraction for the register buffer storage (struct
        fpstate) which allows to dynamically size the buffer at runtime
        by flipping the pointer to the buffer container from the default
        container which is embedded in task_struct::tread::fpu to a
        dynamically allocated container with a larger register buffer.

      - Convert the code over to the new fpstate mechanism.

      - Consolidate the KVM FPU handling by moving the FPU related code
        into the FPU core which removes the number of exports and avoids
        adding even more export when AMX has to be supported in KVM.
        This also removes duplicated code which was of course
        unnecessary different and incomplete in the KVM copy.

      - Simplify the KVM FPU buffer handling by utilizing the new
        fpstate container and just switching the buffer pointer from the
        user space buffer to the KVM guest buffer when entering
        vcpu_run() and flipping it back when leaving the function. This
        cuts the memory requirements of a vCPU for FPU buffers in half
        and avoids pointless memory copy operations.

        This also solves the so far unresolved problem of adding AMX
        support because the current FPU buffer handling of KVM inflicted
        a circular dependency between adding AMX support to the core and
        to KVM. With the new scheme of switching fpstate AMX support can
        be added to the core code without affecting KVM.

      - Replace various variables with proper data structures so the
        extra information required for adding dynamically enabled FPU
        features (AMX) can be added in one place

 - Add AMX (Advanced Matrix eXtensions) support (finally):

   AMX is a large XSTATE component which is going to be available with
   Saphire Rapids XEON CPUs. The feature comes with an extra MSR
   (MSR_XFD) which allows to trap the (first) use of an AMX related
   instruction, which has two benefits:

    1) It allows the kernel to control access to the feature

    2) It allows the kernel to dynamically allocate the large register
       state buffer instead of burdening every task with the the extra
       8K or larger state storage.

   It would have been great to gain this kind of control already with
   AVX512.

   The support comes with the following infrastructure components:

    1) arch_prctl() to
        - read the supported features (equivalent to XGETBV(0))
        - read the permitted features for a task
        - request permission for a dynamically enabled feature

       Permission is granted per process, inherited on fork() and
       cleared on exec(). The permission policy of the kernel is
       restricted to sigaltstack size validation, but the syscall
       obviously allows further restrictions via seccomp etc.

    2) A stronger sigaltstack size validation for sys_sigaltstack(2)
       which takes granted permissions and the potentially resulting
       larger signal frame into account. This mechanism can also be used
       to enforce factual sigaltstack validation independent of dynamic
       features to help with finding potential victims of the 2K
       sigaltstack size constant which is broken since AVX512 support
       was added.

    3) Exception handling for #NM traps to catch first use of a extended
       feature via a new cause MSR. If the exception was caused by the
       use of such a feature, the handler checks permission for that
       feature. If permission has not been granted, the handler sends a
       SIGILL like the #UD handler would do if the feature would have
       been disabled in XCR0. If permission has been granted, then a new
       fpstate which fits the larger buffer requirement is allocated.

       In the unlikely case that this allocation fails, the handler
       sends SIGSEGV to the task. That's not elegant, but unavoidable as
       the other discussed options of preallocation or full per task
       permissions come with their own set of horrors for kernel and/or
       userspace. So this is the lesser of the evils and SIGSEGV caused
       by unexpected memory allocation failures is not a fundamentally
       new concept either.

       When allocation succeeds, the fpstate properties are filled in to
       reflect the extended feature set and the resulting sizes, the
       fpu::fpstate pointer is updated accordingly and the trap is
       disarmed for this task permanently.

    4) Enumeration and size calculations

    5) Trap switching via MSR_XFD

       The XFD (eXtended Feature Disable) MSR is context switched with
       the same life time rules as the FPU register state itself. The
       mechanism is keyed off with a static key which is default
       disabled so !AMX equipped CPUs have zero overhead. On AMX enabled
       CPUs the overhead is limited by comparing the tasks XFD value
       with a per CPU shadow variable to avoid redundant MSR writes. In
       case of switching from a AMX using task to a non AMX using task
       or vice versa, the extra MSR write is obviously inevitable.

       All other places which need to be aware of the variable feature
       sets and resulting variable sizes are not affected at all because
       they retrieve the information (feature set, sizes) unconditonally
       from the fpstate properties.

    6) Enable the new AMX states

   Note, this is relatively new code despite the fact that AMX support
   is in the works for more than a year now.

   The big refactoring of the FPU code, which allowed to do a proper
   integration has been started exactly 3 weeks ago. Refactoring of the
   existing FPU code and of the original AMX patches took a week and has
   been subject to extensive review and testing. The only fallout which
   has not been caught in review and testing right away was restricted
   to AMX enabled systems, which is completely irrelevant for anyone
   outside Intel and their early access program. There might be dragons
   lurking as usual, but so far the fine grained refactoring has held up
   and eventual yet undetected fallout is bisectable and should be
   easily addressable before the 5.16 release. Famous last words...

   Many thanks to Chang Bae and Dave Hansen for working hard on this and
   also to the various test teams at Intel who reserved extra capacity
   to follow the rapid development of this closely which provides the
   confidence level required to offer this rather large update for
   inclusion into 5.16-rc1

* tag 'x86-fpu-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (110 commits)
  Documentation/x86: Add documentation for using dynamic XSTATE features
  x86/fpu: Include vmalloc.h for vzalloc()
  selftests/x86/amx: Add context switch test
  selftests/x86/amx: Add test cases for AMX state management
  x86/fpu/amx: Enable the AMX feature in 64-bit mode
  x86/fpu: Add XFD handling for dynamic states
  x86/fpu: Calculate the default sizes independently
  x86/fpu/amx: Define AMX state components and have it used for boot-time checks
  x86/fpu/xstate: Prepare XSAVE feature table for gaps in state component numbers
  x86/fpu/xstate: Add fpstate_realloc()/free()
  x86/fpu/xstate: Add XFD #NM handler
  x86/fpu: Update XFD state where required
  x86/fpu: Add sanity checks for XFD
  x86/fpu: Add XFD state to fpstate
  x86/msr-index: Add MSRs for XFD
  x86/cpufeatures: Add eXtended Feature Disabling (XFD) feature bit
  x86/fpu: Reset permission and fpstate on exec()
  x86/fpu: Prepare fpu_clone() for dynamically enabled features
  x86/fpu/signal: Prepare for variable sigframe length
  x86/signal: Use fpu::__state_user_size for sigalt stack validation
  ...
2021-11-01 14:03:56 -07:00
Linus Torvalds
9a7e0a90a4 Merge tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Thomas Gleixner:

 - Revert the printk format based wchan() symbol resolution as it can
   leak the raw value in case that the symbol is not resolvable.

 - Make wchan() more robust and work with all kind of unwinders by
   enforcing that the task stays blocked while unwinding is in progress.

 - Prevent sched_fork() from accessing an invalid sched_task_group

 - Improve asymmetric packing logic

 - Extend scheduler statistics to RT and DL scheduling classes and add
   statistics for bandwith burst to the SCHED_FAIR class.

 - Properly account SCHED_IDLE entities

 - Prevent a potential deadlock when initial priority is assigned to a
   newly created kthread. A recent change to plug a race between cpuset
   and __sched_setscheduler() introduced a new lock dependency which is
   now triggered. Break the lock dependency chain by moving the priority
   assignment to the thread function.

 - Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.

 - Improve idle balancing in general and especially for NOHZ enabled
   systems.

 - Provide proper interfaces for live patching so it does not have to
   fiddle with scheduler internals.

 - Add cluster aware scheduling support.

 - A small set of tweaks for RT (irqwork, wait_task_inactive(), various
   scheduler options and delaying mmdrop)

 - The usual small tweaks and improvements all over the place

* tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
  sched/fair: Cleanup newidle_balance
  sched/fair: Remove sysctl_sched_migration_cost condition
  sched/fair: Wait before decaying max_newidle_lb_cost
  sched/fair: Skip update_blocked_averages if we are defering load balance
  sched/fair: Account update_blocked_averages in newidle_balance cost
  x86: Fix __get_wchan() for !STACKTRACE
  sched,x86: Fix L2 cache mask
  sched/core: Remove rq_relock()
  sched: Improve wake_up_all_idle_cpus() take #2
  irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT
  irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT
  irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
  sched/rt: Annotate the RT balancing logic irqwork as IRQ_WORK_HARD_IRQ
  sched: Add cluster scheduler level for x86
  sched: Add cluster scheduler level in core and related Kconfig for ARM64
  topology: Represent clusters of CPUs within a die
  sched: Disable -Wunused-but-set-variable
  sched: Add wrapper for get_wchan() to keep task blocked
  x86: Fix get_wchan() to support the ORC unwinder
  proc: Use task_is_running() for wchan in /proc/$pid/stat
  ...
2021-11-01 13:48:52 -07:00
Linus Torvalds
43aa0a195f Merge tag 'objtool-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool updates from Thomas Gleixner:

 - Improve retpoline code patching by separating it from alternatives
   which reduces memory footprint and allows to do better optimizations
   in the actual runtime patching.

 - Add proper retpoline support for x86/BPF

 - Address noinstr warnings in x86/kvm, lockdep and paravirtualization
   code

 - Add support to handle pv_opsindirect calls in the noinstr analysis

 - Classify symbols upfront and cache the result to avoid redundant
   str*cmp() invocations.

 - Add a CFI hash to reduce memory consumption which also reduces
   runtime on a allyesconfig by ~50%

 - Adjust XEN code to make objtool handling more robust and as a side
   effect to prevent text fragmentation due to placement of the
   hypercall page.

* tag 'objtool-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
  bpf,x86: Respect X86_FEATURE_RETPOLINE*
  bpf,x86: Simplify computing label offsets
  x86,bugs: Unconditionally allow spectre_v2=retpoline,amd
  x86/alternative: Add debug prints to apply_retpolines()
  x86/alternative: Try inline spectre_v2=retpoline,amd
  x86/alternative: Handle Jcc __x86_indirect_thunk_\reg
  x86/alternative: Implement .retpoline_sites support
  x86/retpoline: Create a retpoline thunk array
  x86/retpoline: Move the retpoline thunk declarations to nospec-branch.h
  x86/asm: Fixup odd GEN-for-each-reg.h usage
  x86/asm: Fix register order
  x86/retpoline: Remove unused replacement symbols
  objtool,x86: Replace alternatives with .retpoline_sites
  objtool: Shrink struct instruction
  objtool: Explicitly avoid self modifying code in .altinstr_replacement
  objtool: Classify symbols
  objtool: Support pv_opsindirect calls for noinstr
  x86/xen: Rework the xen_{cpu,irq,mmu}_opsarrays
  x86/xen: Mark xen_force_evtchn_callback() noinstr
  x86/xen: Make irq_disable() noinstr
  ...
2021-11-01 13:24:43 -07:00
Peter Zijlstra
f8a66d608a x86,bugs: Unconditionally allow spectre_v2=retpoline,amd
Currently Linux prevents usage of retpoline,amd on !AMD hardware, this
is unfriendly and gets in the way of testing. Remove this restriction.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120310.487348118@infradead.org
2021-10-28 23:25:29 +02:00
Tianyu Lan
af788f355e x86/hyperv: Initialize shared memory boundary in the Isolation VM.
Hyper-V exposes shared memory boundary via cpuid
HYPERV_CPUID_ISOLATION_CONFIG and store it in the
shared_gpa_boundary of ms_hyperv struct. This prepares
to share memory with host for SNP guest.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-3-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28 10:47:52 +00:00
Tianyu Lan
0cc4f6d9f0 x86/hyperv: Initialize GHCB page in Isolation VM
Hyperv exposes GHCB page via SEV ES GHCB MSR for SNP guest
to communicate with hypervisor. Map GHCB page for all
cpus to read/write MSR register and submit hvcall request
via ghcb page.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-2-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28 10:47:52 +00:00
Dave Airlie
970eae1560 BackMerge tag 'v5.15-rc7' into drm-next
The msm next tree is based on rc3, so let's just backmerge rc7 before pulling it in.

Signed-off-by: Dave Airlie <airlied@redhat.com>
2021-10-28 14:59:38 +10:00
Chang S. Bae
2308ee57d9 x86/fpu/amx: Enable the AMX feature in 64-bit mode
Add the AMX state components in XFEATURE_MASK_USER_SUPPORTED and the
TILE_DATA component to the dynamic states and update the permission check
table accordingly.

This is only effective on 64 bit kernels as for 32bit kernels
XFEATURE_MASK_TILE is defined as 0.

TILE_DATA is caller-saved state and the only dynamic state. Add build time
sanity check to ensure the assumption that every dynamic feature is caller-
saved.

Make AMX state depend on XFD as it is dynamic feature.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211021225527.10184-24-chang.seok.bae@intel.com
2021-10-26 10:53:03 +02:00