If the guest requests string I/O from the hypervisor via VMGEXIT,
SW_EXITINFO2 will contain the REP count. However, sev_es_string_io
was incorrectly treating it as the size of the GHCB buffer in
bytes.
This fixes the "outsw" test in the experimental SEV tests of
kvm-unit-tests.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reported-by: Marc Orr <marcorr@google.com>
Tested-by: Marc Orr <marcorr@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In kvm_vcpu_block, the current task is set to TASK_INTERRUPTIBLE before
making a final check whether the vCPU should be woken from HLT by any
incoming interrupt.
This is a problem for the get_user() in __kvm_xen_has_interrupt(), which
really shouldn't be sleeping when the task state has already been set.
I think it's actually harmless as it would just manifest itself as a
spurious wakeup, but it's causing a debug warning:
[ 230.963649] do not call blocking ops when !TASK_RUNNING; state=1 set at [<00000000b6bcdbc9>] prepare_to_swait_exclusive+0x30/0x80
Fix the warning by turning it into an *explicit* spurious wakeup. When
invoked with !task_is_running(current) (and we might as well add
in_atomic() there while we're at it), just return 1 to indicate that
an IRQ is pending, which will cause a wakeup and then something will
call it again in a context that *can* sleep so it can fault the page
back in.
Cc: stable@vger.kernel.org
Fixes: 40da8ccd72 ("KVM: x86/xen: Add event channel interrupt vector upcall")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <168bf8c689561da904e48e2ff5ae4713eaef9e2d.camel@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For the upcoming AMX support it's necessary to do a proper integration with
KVM. Currently KVM allocates two FPU structs which are used for saving the user
state of the vCPU thread and restoring the guest state when entering
vcpu_run() and doing the reverse operation before leaving vcpu_run().
With the new fpstate mechanism this can be reduced to one extra buffer by
swapping the fpstate pointer in current::thread::fpu. This makes the
upcoming support for AMX and XFD simpler because then fpstate information
(features, sizes, xfd) are always consistent and it does not require any
nasty workarounds.
Convert the KVM FPU code over to this new scheme.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211022185313.019454292@linutronix.de
Pull more x86 kvm fixes from Paolo Bonzini:
- Cache coherency fix for SEV live migration
- Fix for instruction emulation with PKU
- fixes for rare delaying of interrupt delivery
- fix for SEV-ES buffer overflow
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: SEV-ES: go over the sev_pio_data buffer in multiple passes if needed
KVM: SEV-ES: keep INS functions together
KVM: x86: remove unnecessary arguments from complete_emulator_pio_in
KVM: x86: split the two parts of emulator_pio_in
KVM: SEV-ES: clean up kvm_sev_es_ins/outs
KVM: x86: leave vcpu->arch.pio.count alone in emulator_pio_in_out
KVM: SEV-ES: rename guest_ins_data to sev_pio_data
KVM: SEV: Flush cache on non-coherent systems before RECEIVE_UPDATE_DATA
KVM: MMU: Reset mmu->pkru_mask to avoid stale data
KVM: nVMX: promptly process interrupts delivered while in guest mode
KVM: x86: check for interrupts before deciding whether to exit the fast path
Unregister KVM's posted interrupt wakeup handler during unsetup so that a
spurious interrupt that arrives after kvm_intel.ko is unloaded doesn't
call into freed memory.
Fixes: bf9f6ac8d7 ("KVM: Update Posted-Interrupts Descriptor when vCPU is blocked")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211009001107.3936588-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use a rw_semaphore instead of a mutex to coordinate APICv updates so that
vCPUs responding to requests can take the lock for read and run in
parallel. Using a mutex forces serialization of vCPUs even though
kvm_vcpu_update_apicv() only touches data local to that vCPU or is
protected by a different lock, e.g. SVM's ir_list_lock.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022004927.1448382-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move SVM's assertion that vCPU's APICv state is consistent with its VM's
state out of svm_vcpu_run() and into x86's common inner run loop. The
assertion and underlying logic is not unique to SVM, it's just that SVM
has more inhibiting conditions and thus is more likely to run headfirst
into any KVM bugs.
Add relevant comments to document exactly why the update path has unusual
ordering between the update the kick, why said ordering is safe, and also
the basic rules behind the assertion in the run loop.
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022004927.1448382-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The PIO scratch buffer is larger than a single page, and therefore
it is not possible to copy it in a single step to vcpu->arch/pio_data.
Bound each call to emulator_pio_in/out to a single page; keep
track of how many I/O operations are left in vcpu->arch.sev_pio_count,
so that the operation can be restarted in the complete_userspace_io
callback.
For OUT, this means that the previous kvm_sev_es_outs implementation
becomes an iterator of the loop, and we can consume the sev_pio_data
buffer before leaving to userspace.
For IN, instead, consuming the buffer and decreasing sev_pio_count
is always done in the complete_userspace_io callback, because that
is when the memcpy is done into sev_pio_data.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reported-by: Felix Wilhelm <fwilhelm@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Make the diff a little nicer when we actually get to fixing
the bug. No functional change intended.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
complete_emulator_pio_in can expect that vcpu->arch.pio has been filled in,
and therefore does not need the size and count arguments. This makes things
nicer when the function is called directly from a complete_userspace_io
callback.
No functional change intended.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
emulator_pio_in handles both the case where the data is pending in
vcpu->arch.pio.count, and the case where I/O has to be done via either
an in-kernel device or a userspace exit. For SEV-ES we would like
to split these, to identify clearly the moment at which the
sev_pio_data is consumed. To this end, create two different
functions: __emulator_pio_in fills in vcpu->arch.pio.count, while
complete_emulator_pio_in clears it and releases vcpu->arch.pio.data.
Because this patch has to be backported, things are left a bit messy.
kernel_pio() operates on vcpu->arch.pio, which leads to emulator_pio_in()
having with two calls to complete_emulator_pio_in(). It will be fixed
in the next release.
While at it, remove the unused void* val argument of emulator_pio_in_out.
The function currently hardcodes vcpu->arch.pio_data as the
source/destination buffer, which sucks but will be fixed after the more
severe SEV-ES buffer overflow.
No functional change intended.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A few very small cleanups to the functions, smushed together because
the patch is already very small like this:
- inline emulator_pio_in_emulated and emulator_pio_out_emulated,
since we already have the vCPU
- remove the data argument and pull setting vcpu->arch.sev_pio_data into
the caller
- remove unnecessary clearing of vcpu->arch.pio.count when
emulation is done by the kernel (and therefore vcpu->arch.pio.count
is already clear on exit from emulator_pio_in and emulator_pio_out).
No functional change intended.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently emulator_pio_in clears vcpu->arch.pio.count twice if
emulator_pio_in_out performs kernel PIO. Move the clear into
emulator_pio_out where it is actually necessary.
No functional change intended.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We will be using this field for OUTS emulation as well, in case the
data that is pushed via OUTS spans more than one page. In that case,
there will be a need to save the data pointer across exits to userspace.
So, change the name to something that refers to any kind of PIO.
Also spell out what it is used for, namely SEV-ES.
No functional change intended.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Extract the zapping of rmaps, a.k.a. legacy MMU, for a gfn range to a
separate helper to clean up the unholy mess that kvm_zap_gfn_range() has
become. In addition to deep nesting, the rmaps zapping spreads out the
declaration of several variables and is generally a mess. Clean up the
mess now so that future work to improve the memslots implementation
doesn't need to deal with it.
Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022010005.1454978-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove an unnecessary remote TLB flush in kvm_zap_gfn_range() now that
said function holds mmu_lock for write for its entire duration. The
flush was added by the now-reverted commit to allow TDP MMU to flush while
holding mmu_lock for read, as the transition from write=>read required
dropping the lock and thus a pending flush needed to be serviced.
Fixes: 5a324c24b6 ("Revert "KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock"")
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022010005.1454978-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The commit 578e1c4db2 ("kvm: x86: Avoid taking MMU lock
in kvm_mmu_sync_roots if no sync is needed") added smp_wmb() in
mmu_try_to_unsync_pages(), but the corresponding smp_load_acquire() isn't
used on the load of SPTE.W. smp_load_acquire() orders _subsequent_
loads after sp->is_unsync; it does not order _earlier_ loads before
the load of sp->is_unsync.
This has no functional change; smp_rmb() is a NOP on x86, and no
compiler barrier is required because there is a VMEXIT between the
load of SPTE.W and kvm_mmu_snc_roots.
Cc: Junaid Shahid <junaids@google.com>
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211019110154.4091-4-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The commit 21823fbda5 ("KVM: x86: Invalidate all PGDs for the
current PCID on MOV CR3 w/ flush") invalidates all PGDs for the specific
PCID and in the case of PCID is disabled, it includes all PGDs in the
prev_roots and the commit made prev_roots totally unused in this case.
Not using prev_roots fixes a problem when CR4.PCIDE is changed 0 -> 1
before the said commit:
(CR4.PCIDE=0, CR4.PGE=1; CR3=cr3_a; the page for the guest
RIP is global; cr3_b is cached in prev_roots)
modify page tables under cr3_b
the shadow root of cr3_b is unsync in kvm
INVPCID single context
the guest expects the TLB is clean for PCID=0
change CR4.PCIDE 0 -> 1
switch to cr3_b with PCID=0,NOFLUSH=1
No sync in kvm, cr3_b is still unsync in kvm
jump to the page that was modified in step 1
shadow page tables point to the wrong page
It is a very unlikely case, but it shows that stale prev_roots can be
a problem after CR4.PCIDE changes from 0 to 1. However, to fix this
case, the commit disabled caching CR3 in prev_roots altogether when PCID
is disabled. Not all CPUs have PCID; especially the PCID support
for AMD CPUs is kind of recent. To restore the prev_roots optimization
for CR4.PCIDE=0, flush the whole MMU (including all prev_roots) when
CR4.PCIDE changes.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211019110154.4091-3-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The KVM doesn't know whether any TLB for a specific pcid is cached in
the CPU when tdp is enabled. So it is better to flush all the guest
TLB when invalidating any single PCID context.
The case is very rare or even impossible since KVM generally doesn't
intercept CR3 write or INVPCID instructions when tdp is enabled, so the
fix is mostly for the sake of overall robustness.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211019110154.4091-2-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
X86_CR4_PGE doesn't participate in kvm_mmu_role, so the mmu context
doesn't need to be reset. It is only required to flush all the guest
tlb.
It is also inconsistent that X86_CR4_PGE is in KVM_MMU_CR4_ROLE_BITS
while kvm_mmu_role doesn't use X86_CR4_PGE. So X86_CR4_PGE is also
removed from KVM_MMU_CR4_ROLE_BITS.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210919024246.89230-3-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
SDM mentioned that, RDPMC:
IF (((CR4.PCE = 1) or (CPL = 0) or (CR0.PE = 0)) and (ECX indicates a supported counter))
THEN
EAX := counter[31:0];
EDX := ZeroExtend(counter[MSCB:32]);
ELSE (* ECX is not valid or CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1 *)
#GP(0);
FI;
Let's add a comment why CR0.PE isn't tested since it's impossible for CPL to be >0 if
CR0.PE=0.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1634724836-73721-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paul pointed out the error messages when KVM fails to load are unhelpful
in understanding exactly what went wrong if userspace probes the "wrong"
module.
Add a mandatory kvm_x86_ops field to track vendor module names, kvm_intel
and kvm_amd, and use the name for relevant error message when KVM fails
to load so that the user knows which module failed to load.
Opportunistically tweak the "disabled by bios" error message to clarify
that _support_ was disabled, not that the module itself was magically
disabled by BIOS.
Suggested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211018183929.897461-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, the NX huge page recovery thread wakes up every minute and
zaps 1/nx_huge_pages_recovery_ratio of the total number of split NX
huge pages at a time. This is intended to ensure that only a
relatively small number of pages get zapped at a time. But for very
large VMs (or more specifically, VMs with a large number of
executable pages), a period of 1 minute could still result in this
number being too high (unless the ratio is changed significantly,
but that can result in split pages lingering on for too long).
This change makes the period configurable instead of fixing it at
1 minute. Users of large VMs can then adjust the period and/or the
ratio to reduce the number of pages zapped at one time while still
maintaining the same overall duration for cycling through the
entire list. By default, KVM derives a period from the ratio such
that a page will remain on the list for 1 hour on average.
Signed-off-by: Junaid Shahid <junaids@google.com>
Message-Id: <20211020010627.305925-1-junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
SDM section 18.2.3 mentioned that:
"IA32_PERF_GLOBAL_OVF_CTL MSR allows software to clear overflow indicator(s) of
any general-purpose or fixed-function counters via a single WRMSR."
It is R/W mentioned by SDM, we read this msr on bare-metal during perf testing,
the value is always 0 for ICX/SKX boxes on hands. Let's fill get_msr
MSR_CORE_PERF_GLOBAL_OVF_CTRL w/ 0 as hardware behavior and drop
global_ovf_ctrl variable.
Tested-by: Like Xu <likexu@tencent.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1634631160-67276-2-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
slot_handle_leaf is a misnomer because it only operates on 4K SPTEs
whereas "leaf" is used to describe any valid terminal SPTE (4K or
large page). Rename slot_handle_leaf to slot_handle_level_4k to
avoid confusion.
Making this change makes it more obvious there is a benign discrepency
between the legacy MMU and the TDP MMU when it comes to dirty logging.
The legacy MMU only iterates through 4K SPTEs when zapping for
collapsing and when clearing D-bits. The TDP MMU, on the other hand,
iterates through SPTEs on all levels.
The TDP MMU behavior of zapping SPTEs at all levels is technically
overkill for its current dirty logging implementation, which always
demotes to 4k SPTES, but both the TDP MMU and legacy MMU zap if and only
if the SPTE can be replaced by a larger page, i.e. will not spuriously
zap 2m (or larger) SPTEs. Opportunistically add comments to explain this
discrepency in the code.
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20211019162223.3935109-1-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
"prefetch", "prefault" and "speculative" are used throughout KVM to mean
the same thing. Use a single name, standardizing on "prefetch" which
is already used by various functions such as direct_pte_prefetch,
FNAME(prefetch_gpte), FNAME(pte_prefetch), etc.
Suggested-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Unify the flags for rmaps and page tracking data, using a
single flag in struct kvm_arch and a single loop to go
over all the address spaces and memslots. This avoids
code duplication between alloc_all_memslots_rmaps and
kvm_page_track_enable_mmu_write_tracking.
Signed-off-by: David Stevens <stevensd@chromium.org>
[This patch is the delta between David's v2 and v3, with conflicts
fixed and my own commit message. - Paolo]
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since commit c300ab9f08 ("KVM: x86: Replace late check_nested_events() hack with
more precise fix") there is no longer the certainty that check_nested_events()
tries to inject an external interrupt vmexit to L1 on every call to vcpu_enter_guest.
Therefore, even in that case we need to set KVM_REQ_EVENT. This ensures
that inject_pending_event() is called, and from there kvm_check_nested_events().
Fixes: c300ab9f08 ("KVM: x86: Replace late check_nested_events() hack with more precise fix")
Cc: stable@vger.kernel.org
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The kvm_x86_sync_pir_to_irr callback can sometimes set KVM_REQ_EVENT.
If that happens exactly at the time that an exit is handled as
EXIT_FASTPATH_REENTER_GUEST, vcpu_enter_guest will go incorrectly
through the loop that calls kvm_x86_run, instead of processing
the request promptly.
Fixes: 379a3c8ee4 ("KVM: VMX: Optimize posted-interrupt delivery for timer fastpath")
Cc: stable@vger.kernel.org
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull kvm fixes from Paolo Bonzini:
"Tools:
- kvm_stat: do not show halt_wait_ns since it is not a cumulative statistic
x86:
- clean ups and fixes for bus lock vmexit and lazy allocation of rmaps
- two fixes for SEV-ES (one more coming as soon as I get reviews)
- fix for static_key underflow
ARM:
- Properly refcount pages used as a concatenated stage-2 PGD
- Fix missing unlock when detecting the use of MTE+VM_SHARED"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: SEV-ES: reduce ghcb_sa_len to 32 bits
KVM: VMX: Remove redundant handling of bus lock vmexit
KVM: kvm_stat: do not show halt_wait_ns
KVM: x86: WARN if APIC HW/SW disable static keys are non-zero on unload
Revert "KVM: x86: Open code necessary bits of kvm_lapic_set_base() at vCPU RESET"
KVM: SEV-ES: Set guest_state_protected after VMSA update
KVM: X86: fix lazy allocation of rmaps
KVM: SEV-ES: fix length of string I/O
KVM: arm64: Release mmap_lock when using VM_SHARED with MTE
KVM: arm64: Report corrupted refcount at EL2
KVM: arm64: Fix host stage-2 PGD refcount
KVM: s390: Function documentation fixes
Copying a user space buffer to the memory buffer is already available in
the FPU core. The copy mechanism in KVM lacks sanity checks and needs to
use cpuid() to lookup the offset of each component, while the FPU core has
this information cached.
Make the FPU core variant accessible for KVM and replace the home brewed
mechanism.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/20211015011539.134065207@linutronix.de
