Commit Graph

345 Commits

Author SHA1 Message Date
Mohammed Gamal
fb4616f431 KVM: x86 emulator: Add std and cld instructions (opcodes 0xfc-0xfd)
This adds the std and cld instructions to the emulator.

Encountered while running the BIOS with invalid guest
state emulation enabled.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:25 +02:00
Joerg Roedel
a89c1ad270 KVM: add MC5_MISC msr read support
Currently KVM implements MC0-MC4_MISC read support. When booting Linux this
results in KVM warnings in the kernel log when the guest tries to read
MC5_MISC. Fix this warnings with this patch.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:24 +02:00
Avi Kivity
48d1503949 KVM: SVM: No need to unprotect memory during event injection when using npt
No memory is protected anyway.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:24 +02:00
Avi Kivity
3201b5d9f0 KVM: MMU: Fix setting the accessed bit on non-speculative sptes
The accessed bit was accidentally turned on in a random flag word, rather
than, the spte itself, which was lucky, since it used the non-EPT compatible
PT_ACCESSED_MASK.

Fix by turning the bit on in the spte and changing it to use the portable
accessed mask.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:24 +02:00
Avi Kivity
171d595d3b KVM: MMU: Flush tlbs after clearing write permission when accessing dirty log
Otherwise, the cpu may allow writes to the tracked pages, and we lose
some display bits or fail to migrate correctly.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:24 +02:00
Avi Kivity
2245a28fe2 KVM: MMU: Add locking around kvm_mmu_slot_remove_write_access()
It was generally safe due to slots_lock being held for write, but it wasn't
very nice.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:24 +02:00
Avi Kivity
bc2d429979 KVM: MMU: Account for npt/ept/realmode page faults
Now that two-dimensional paging is becoming common, account for tdp page
faults.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:23 +02:00
Mohammed Gamal
a5e2e82b8b KVM: x86 emulator: Add mov r, imm instructions (opcodes 0xb0-0xbf)
The emulator only supported one instance of mov r, imm instruction
(opcode 0xb8), this adds the rest of these instructions.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:23 +02:00
Avi Kivity
acee3c04e8 KVM: Allocate guest memory as MAP_PRIVATE, not MAP_SHARED
There is no reason to share internal memory slots with fork()ed instances.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:23 +02:00
Avi Kivity
abb9e0b8e3 KVM: MMU: Convert the paging mode shadow walk to use the generic walker
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:23 +02:00
Avi Kivity
140754bc80 KVM: MMU: Convert direct maps to use the generic shadow walker
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:23 +02:00
Avi Kivity
3d000db568 KVM: MMU: Add generic shadow walker
We currently walk the shadow page tables in two places: direct map (for
real mode and two dimensional paging) and paging mode shadow.  Since we
anticipate requiring a third walk (for invlpg), it makes sense to have
a generic facility for shadow walk.

This patch adds such a shadow walker, walks the page tables and calls a
method for every spte encountered.  The method can examine the spte,
modify it, or even instantiate it.  The walk can be aborted by returning
nonzero from the method.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:23 +02:00
Avi Kivity
6c41f428b7 KVM: MMU: Infer shadow root level in direct_map()
In all cases the shadow root level is available in mmu.shadow_root_level,
so there is no need to pass it as a parameter.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:22 +02:00
Avi Kivity
6e37d3dc3e KVM: MMU: Unify direct map 4K and large page paths
The two paths are equivalent except for one argument, which is already
available.  Merge the two codepaths.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:22 +02:00
Avi Kivity
135f8c2b07 KVM: MMU: Move SHADOW_PT_INDEX to mmu.c
It is not specific to the paging mode, so can be made global (and reusable).

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:22 +02:00
Avi Kivity
6eb06cb286 KVM: x86 emulator: remove bad ByteOp specifier from NEG descriptor
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:22 +02:00
roel kluin
41afa02587 KVM: x86 emulator: remove duplicate SrcImm
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:21 +02:00
Avi Kivity
f4bbd9aaaa KVM: Load real mode segments correctly
Real mode segments to not reference the GDT or LDT; they simply compute
base = selector * 16.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:21 +02:00
Avi Kivity
a16b20da87 KVM: VMX: Change segment dpl at reset to 3
This is more emulation friendly, if not 100% correct.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:21 +02:00
Avi Kivity
5706be0daf KVM: VMX: Change cs reset state to be a data segment
Real mode cs is a data segment, not a code segment.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:21 +02:00
Harvey Harrison
ee032c993e KVM: make irq ack notifier functions static
sparse says:

arch/x86/kvm/x86.c:107:32: warning: symbol 'kvm_find_assigned_dev' was not declared. Should it be static?
arch/x86/kvm/i8254.c:225:6: warning: symbol 'kvm_pit_ack_irq' was not declared. Should it be static?

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:21 +02:00
Amit Shah
29c8fa32c5 KVM: Use kvm_set_irq to inject interrupts
... instead of using the pic and ioapic variants

Signed-off-by: Amit Shah <amit.shah@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:21 +02:00
Amit Shah
94c935a1ee KVM: SVM: Fix typo
Fix typo in as-yet unused macro definition.

Signed-off-by: Amit Shah <amit.shah@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:20 +02:00
Mohammed Gamal
a89a8fb93b KVM: VMX: Modify mode switching and vmentry functions
This patch modifies mode switching and vmentry function in order to
drive invalid guest state emulation.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:20 +02:00
Mohammed Gamal
ea953ef0ca KVM: VMX: Add invalid guest state handler
This adds the invalid guest state handler function which invokes the x86
emulator until getting the guest to a VMX-friendly state.

[avi: leave atomic context if scheduling]
[guillaume: return to atomic context correctly]

Signed-off-by: Laurent Vivier <laurent.vivier@bull.net>
Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:20 +02:00
Mohammed Gamal
04fa4d3211 KVM: VMX: Add module parameter and emulation flag.
The patch adds the module parameter required to enable emulating invalid
guest state, as well as the emulation_required flag used to drive
emulation whenever needed.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:20 +02:00
Mohammed Gamal
648dfaa7df KVM: VMX: Add Guest State Validity Checks
This patch adds functions to check whether guest state is VMX compliant.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:20 +02:00
Amit Shah
6762b7299a KVM: Device assignment: Check for privileges before assigning irq
Even though we don't share irqs at the moment, we should ensure
regular user processes don't try to allocate system resources.

We check for capability to access IO devices (CAP_SYS_RAWIO) before
we request_irq on behalf of the guest.

Noticed by Avi.

Signed-off-by: Amit Shah <amit.shah@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:20 +02:00
Avi Kivity
dc7404cea3 KVM: Handle spurious acks for PIT interrupts
Spurious acks can be generated, for example if the PIC is being reset.
Handle those acks gracefully rather than flooding the log with warnings.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:19 +02:00
Marcelo Tosatti
85428ac7c3 KVM: fix i8259 reset irq acking
The irq ack during pic reset has three problems:

- Ignores slave/master PIC, using gsi 0-8 for both.
- Generates an ACK even if the APIC is in control.
- Depends upon IMR being clear, which is broken if the irq was masked
at the time it was generated.

The last one causes the BIOS to hang after the first reboot of
Windows installation, since PIT interrupts stop.

[avi: fix check whether pic interrupts are seen by cpu]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:19 +02:00
Avi Kivity
ecfc79c700 KVM: VMX: Use interrupt queue for !irqchip_in_kernel
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:19 +02:00
Marcelo Tosatti
29415c37f0 KVM: set debug registers after "schedulable" section
The vcpu thread can be preempted after the guest_debug_pre() callback,
resulting in invalid debug registers on the new vcpu.

Move it inside the non-preemptable section.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:19 +02:00
Sheng Yang
464d17c8b7 KVM: VMX: Clean up magic number 0x66 in init_rmode_tss
Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:19 +02:00
Dave Hansen
6ad18fba05 KVM: Reduce stack usage in kvm_pv_mmu_op()
We're in a hot path.  We can't use kmalloc() because
it might impact performance.  So, we just stick the buffer that
we need into the kvm_vcpu_arch structure.  This is used very
often, so it is not really a waste.

We also have to move the buffer structure's definition to the
arch-specific x86 kvm header.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:18 +02:00
Dave Hansen
b772ff362e KVM: Reduce stack usage in kvm_arch_vcpu_ioctl()
[sheng: fix KVM_GET_LAPIC using wrong size]

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:18 +02:00
Dave Hansen
f0d662759a KVM: Reduce kvm stack usage in kvm_arch_vm_ioctl()
On my machine with gcc 3.4, kvm uses ~2k of stack in a few
select functions.  This is mostly because gcc fails to
notice that the different case: statements could have their
stack usage combined.  It overflows very nicely if interrupts
happen during one of these large uses.

This patch uses two methods for reducing stack usage.
1. dynamically allocate large objects instead of putting
   on the stack.
2. Use a union{} member for all of the case variables. This
   tricks gcc into combining them all into a single stack
   allocation. (There's also a comment on this)

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:18 +02:00
Ben-Ami Yassour
4d5c5d0fe8 KVM: pci device assignment
Based on a patch from: Amit Shah <amit.shah@qumranet.com>

This patch adds support for handling PCI devices that are assigned to
the guest.

The device to be assigned to the guest is registered in the host kernel
and interrupt delivery is handled.  If a device is already assigned, or
the device driver for it is still loaded on the host, the device
assignment is failed by conveying a -EBUSY reply to the userspace.

Devices that share their interrupt line are not supported at the moment.

By itself, this patch will not make devices work within the guest.
The VT-d extension is required to enable the device to perform DMA.
Another alternative is PVDMA.

Signed-off-by: Amit Shah <amit.shah@qumranet.com>
Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com>
Signed-off-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:18 +02:00
Marcelo Tosatti
3cf57fed21 KVM: PIT: fix injection logic and count
The PIT injection logic is problematic under the following cases:

1) If there is a higher priority vector to be delivered by the time
kvm_pit_timer_intr_post is invoked ps->inject_pending won't be set.
This opens the possibility for missing many PIT event injections (say if
guest executes hlt at this point).

2) ps->inject_pending is racy with more than two vcpus. Since there's no locking
around read/dec of pt->pending, two vcpu's can inject two interrupts for a single
pt->pending count.

Fix 1 by using an irq ack notifier: only reinject when the previous irq
has been acked. Fix 2 with appropriate locking around manipulation of
pending count and irq_ack by the injection / ack paths.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:17 +02:00
Marcelo Tosatti
f52447261b KVM: irq ack notification
Based on a patch from: Ben-Ami Yassour <benami@il.ibm.com>
which was based on a patch from: Amit Shah <amit.shah@qumranet.com>

Notify IRQ acking on PIC/APIC emulation. The previous patch missed two things:

- Edge triggered interrupts on IOAPIC
- PIC reset with IRR/ISR set should be equivalent to ack (LAPIC probably
needs something similar).

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
CC: Amit Shah <amit.shah@qumranet.com>
CC: Ben-Ami Yassour <benami@il.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:16 +02:00
Avi Kivity
564f15378f KVM: Add irq ack notifier list
This can be used by kvm subsystems that are interested in when
interrupts are acked, for example time drift compensation.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:16 +02:00
Alexander Graf
b5e2fec0eb KVM: Ignore DEBUGCTL MSRs with no effect
Netware writes to DEBUGCTL and reads from the DEBUGCTL and LAST*IP MSRs
without further checks and is really confused to receive a #GP during that.
To make it happy we should just make them stubs, which is exactly what SVM
already does.

Writes to DEBUGCTL that are vendor-specific are resembled to behave as if the
virtual CPU does not know them.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:15 +02:00
Avi Kivity
313dbd49dc KVM: VMX: Avoid vmwrite(HOST_RSP) when possible
Usually HOST_RSP retains its value across guest entries.  Take advantage
of this and avoid a vmwrite() when this is so.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:15 +02:00
Avi Kivity
80e31d4f61 KVM: SVM: Unify register save/restore across 32 and 64 bit hosts
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:14 +02:00
Avi Kivity
c801949ddf KVM: VMX: Unify register save/restore across 32 and 64 bit hosts
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:14 +02:00
Jan Kiszka
77ab6db0a1 KVM: VMX: Reinject real mode exception
As we execute real mode guests in VM86 mode, exception have to be
reinjected appropriately when the guest triggered them. For this purpose
the patch adopts the real-mode injection pattern used in vmx_inject_irq
to vmx_queue_exception, additionally taking care that the IP is set
correctly for #BP exceptions. Furthermore it extends
handle_rmode_exception to reinject all those exceptions that can be
raised in real mode.

This fixes the execution of himem.exe from FreeDOS and also makes its
debug.com work properly.

Note that guest debugging in real mode is broken now. This has to be
fixed by the scheduled debugging infrastructure rework (will be done
once base patches for QEMU have been accepted).

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:14 +02:00
Jan Kiszka
19bd8afdc4 KVM: Consolidate XX_VECTOR defines
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:14 +02:00
Avi Kivity
7edd0ce058 KVM: Consolidate PIC isr clearing into a function
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:14 +02:00
Mohammed Gamal
60bd83a125 KVM: VMX: Remove redundant check in handle_rmode_exception
Since checking for vcpu->arch.rmode.active is already done whenever we
call handle_rmode_exception(), checking it inside the function is redundant.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:13 +02:00
Avi Kivity
f7d9238f5d KVM: VMX: Move interrupt post-processing to vmx_complete_interrupts()
Instead of looking at failed injections in the vm entry path, move
processing to the exit path in vmx_complete_interrupts().  This simplifes
the logic and removes any state that is hidden in vmx registers.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:13 +02:00
Avi Kivity
937a7eaef9 KVM: Add a pending interrupt queue
Similar to the exception queue, this hold interrupts that have been
accepted by the virtual processor core but not yet injected.

Not yet used.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:13 +02:00
Avi Kivity
35920a3569 KVM: VMX: Fix pending exception processing
The vmx code assumes that IDT-Vectoring can only be set when an exception
is injected due to the exception in question.  That's not true, however:
if the exception is injected correctly, and later another exception occurs
but its delivery is blocked due to a fault, then we will incorrectly assume
the first exception was not delivered.

Fix by unconditionally dequeuing the pending exception, and requeuing it
(or the second exception) if we see it in the IDT-Vectoring field.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:13 +02:00
Avi Kivity
26eef70c3e KVM: Clear exception queue before emulating an instruction
If we're emulating an instruction, either it will succeed, in which case
any previously queued exception will be spurious, or we will requeue the
same exception.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:13 +02:00
Avi Kivity
668f612fa0 KVM: VMX: Move nmi injection failure processing to vm exit path
Instead of processing nmi injection failure in the vm entry path, move
it to the vm exit path (vm_complete_interrupts()).  This separates nmi
injection from nmi post-processing, and moves the nmi state from the VT
state into vcpu state (new variable nmi_injected specifying an injection
in progress).

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:13 +02:00
Avi Kivity
cf393f7566 KVM: Move NMI IRET fault processing to new vmx_complete_interrupts()
Currently most interrupt exit processing is handled on the entry path,
which is confusing.  Move the NMI IRET fault processing to a new function,
vmx_complete_interrupts(), which is called on the vmexit path.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:12 +02:00
Avi Kivity
5b5c6a5a60 KVM: MMU: Simplify kvm_mmu_zap_page()
The twisty maze of conditionals can be reduced.

[joerg: fix tlb flushing]

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:12 +02:00
Avi Kivity
31aa2b44af KVM: MMU: Separate the code for unlinking a shadow page from its parents
Place into own function, in preparation for further cleanups.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:12 +02:00
Amit Shah
867767a365 KVM: Introduce kvm_set_irq to inject interrupts in guests
This function injects an interrupt into the guest given the kvm struct,
the (guest) irq number and the interrupt level.

Signed-off-by: Amit Shah <amit.shah@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:12 +02:00
Marcelo Tosatti
5fdbf9765b KVM: x86: accessors for guest registers
As suggested by Avi, introduce accessors to read/write guest registers.
This simplifies the ->cache_regs/->decache_regs interface, and improves
register caching which is important for VMX, where the cost of
vmcs_read/vmcs_write is significant.

[avi: fix warnings]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:13:57 +02:00
Sheng Yang
ca60dfbb69 KVM: VMX: Rename misnamed msr bits
MSR_IA32_FEATURE_LOCKED is just a bit in fact, which shouldn't be prefixed with
MSR_.  So is MSR_IA32_FEATURE_VMXON_ENABLED.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:13:57 +02:00
Ingo Molnar
0afe2db213 Merge branch 'x86/unify-cpu-detect' into x86-v28-for-linus-phase4-D
Conflicts:
	arch/x86/kernel/cpu/common.c
	arch/x86/kernel/signal_64.c
	include/asm-x86/cpufeature.h
2008-10-11 20:23:20 +02:00
Sheng Yang
534e38b447 KVM: VMX: Always return old for clear_flush_young() when using EPT
As well as discard fake accessed bit and dirty bit of EPT.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-09-11 11:48:19 +03:00
Joerg Roedel
e5eab0cede KVM: SVM: fix guest global tlb flushes with NPT
Accesses to CR4 are intercepted even with Nested Paging enabled. But the code
does not check if the guest wants to do a global TLB flush. So this flush gets
lost. This patch adds the check and the flush to svm_set_cr4.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-09-11 11:39:25 +03:00
Joerg Roedel
44874f8491 KVM: SVM: fix random segfaults with NPT enabled
This patch introduces a guest TLB flush on every NPF exit in KVM. This fixes
random segfaults and #UD exceptions in the guest seen under some workloads
(e.g. long running compile workloads or tbench). A kernbench run with and
without that fix showed that it has a slowdown lower than 0.5%

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-09-11 11:31:53 +03:00
Sheng Yang
315a6558f3 x86: move VMX MSRs to msr-index.h
They are hardware specific MSRs, and we would use them in virtualization
feature detection later.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-10 14:00:55 +02:00
Arjan van de Ven
beb20d52d0 hrtimer: convert kvm to the new hrtimer apis
In order to be able to do range hrtimers we need to use accessor functions
to the "expire" member of the hrtimer struct.
This patch converts KVM to these accessors.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2008-09-05 21:35:07 -07:00
Avi Kivity
cd5998ebfb KVM: MMU: Fix torn shadow pte
The shadow code assigns a pte directly in one place, which is nonatomic on
i386 can can cause random memory references.  Fix by using an atomic setter.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-08-25 17:24:27 +03:00
Avi Kivity
ed84862433 KVM: Advertise synchronized mmu support to userspace
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-29 12:34:02 +03:00
Andrea Arcangeli
e930bffe95 KVM: Synchronize guest physical memory map to host virtual memory map
Synchronize changes to host virtual addresses which are part of
a KVM memory slot to the KVM shadow mmu.  This allows pte operations
like swapping, page migration, and madvise() to transparently work
with KVM.

Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-29 12:33:53 +03:00
Andrea Arcangeli
604b38ac03 KVM: Allow browsing memslots with mmu_lock
This allows reading memslots with only the mmu_lock hold for mmu
notifiers that runs in atomic context and with mmu_lock held.

Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-29 12:33:50 +03:00
Andrea Arcangeli
a1708ce8a3 KVM: Allow reading aliases with mmu_lock
This allows the mmu notifier code to run unalias_gfn with only the
mmu_lock held.  Only alias writes need the mmu_lock held. Readers will
either take the slots_lock in read mode or the mmu_lock.

Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-29 12:33:40 +03:00
Andrea Arcangeli
cddb8a5c14 mmu-notifiers: core
With KVM/GFP/XPMEM there isn't just the primary CPU MMU pointing to pages.
 There are secondary MMUs (with secondary sptes and secondary tlbs) too.
sptes in the kvm case are shadow pagetables, but when I say spte in
mmu-notifier context, I mean "secondary pte".  In GRU case there's no
actual secondary pte and there's only a secondary tlb because the GRU
secondary MMU has no knowledge about sptes and every secondary tlb miss
event in the MMU always generates a page fault that has to be resolved by
the CPU (this is not the case of KVM where the a secondary tlb miss will
walk sptes in hardware and it will refill the secondary tlb transparently
to software if the corresponding spte is present).  The same way
zap_page_range has to invalidate the pte before freeing the page, the spte
(and secondary tlb) must also be invalidated before any page is freed and
reused.

Currently we take a page_count pin on every page mapped by sptes, but that
means the pages can't be swapped whenever they're mapped by any spte
because they're part of the guest working set.  Furthermore a spte unmap
event can immediately lead to a page to be freed when the pin is released
(so requiring the same complex and relatively slow tlb_gather smp safe
logic we have in zap_page_range and that can be avoided completely if the
spte unmap event doesn't require an unpin of the page previously mapped in
the secondary MMU).

The mmu notifiers allow kvm/GRU/XPMEM to attach to the tsk->mm and know
when the VM is swapping or freeing or doing anything on the primary MMU so
that the secondary MMU code can drop sptes before the pages are freed,
avoiding all page pinning and allowing 100% reliable swapping of guest
physical address space.  Furthermore it avoids the code that teardown the
mappings of the secondary MMU, to implement a logic like tlb_gather in
zap_page_range that would require many IPI to flush other cpu tlbs, for
each fixed number of spte unmapped.

To make an example: if what happens on the primary MMU is a protection
downgrade (from writeable to wrprotect) the secondary MMU mappings will be
invalidated, and the next secondary-mmu-page-fault will call
get_user_pages and trigger a do_wp_page through get_user_pages if it
called get_user_pages with write=1, and it'll re-establishing an updated
spte or secondary-tlb-mapping on the copied page.  Or it will setup a
readonly spte or readonly tlb mapping if it's a guest-read, if it calls
get_user_pages with write=0.  This is just an example.

This allows to map any page pointed by any pte (and in turn visible in the
primary CPU MMU), into a secondary MMU (be it a pure tlb like GRU, or an
full MMU with both sptes and secondary-tlb like the shadow-pagetable layer
with kvm), or a remote DMA in software like XPMEM (hence needing of
schedule in XPMEM code to send the invalidate to the remote node, while no
need to schedule in kvm/gru as it's an immediate event like invalidating
primary-mmu pte).

At least for KVM without this patch it's impossible to swap guests
reliably.  And having this feature and removing the page pin allows
several other optimizations that simplify life considerably.

Dependencies:

1) mm_take_all_locks() to register the mmu notifier when the whole VM
   isn't doing anything with "mm".  This allows mmu notifier users to keep
   track if the VM is in the middle of the invalidate_range_begin/end
   critical section with an atomic counter incraese in range_begin and
   decreased in range_end.  No secondary MMU page fault is allowed to map
   any spte or secondary tlb reference, while the VM is in the middle of
   range_begin/end as any page returned by get_user_pages in that critical
   section could later immediately be freed without any further
   ->invalidate_page notification (invalidate_range_begin/end works on
   ranges and ->invalidate_page isn't called immediately before freeing
   the page).  To stop all page freeing and pagetable overwrites the
   mmap_sem must be taken in write mode and all other anon_vma/i_mmap
   locks must be taken too.

2) It'd be a waste to add branches in the VM if nobody could possibly
   run KVM/GRU/XPMEM on the kernel, so mmu notifiers will only enabled if
   CONFIG_KVM=m/y.  In the current kernel kvm won't yet take advantage of
   mmu notifiers, but this already allows to compile a KVM external module
   against a kernel with mmu notifiers enabled and from the next pull from
   kvm.git we'll start using them.  And GRU/XPMEM will also be able to
   continue the development by enabling KVM=m in their config, until they
   submit all GRU/XPMEM GPLv2 code to the mainline kernel.  Then they can
   also enable MMU_NOTIFIERS in the same way KVM does it (even if KVM=n).
   This guarantees nobody selects MMU_NOTIFIER=y if KVM and GRU and XPMEM
   are all =n.

The mmu_notifier_register call can fail because mm_take_all_locks may be
interrupted by a signal and return -EINTR.  Because mmu_notifier_reigster
is used when a driver startup, a failure can be gracefully handled.  Here
an example of the change applied to kvm to register the mmu notifiers.
Usually when a driver startups other allocations are required anyway and
-ENOMEM failure paths exists already.

 struct  kvm *kvm_arch_create_vm(void)
 {
        struct kvm *kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL);
+       int err;

        if (!kvm)
                return ERR_PTR(-ENOMEM);

        INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);

+       kvm->arch.mmu_notifier.ops = &kvm_mmu_notifier_ops;
+       err = mmu_notifier_register(&kvm->arch.mmu_notifier, current->mm);
+       if (err) {
+               kfree(kvm);
+               return ERR_PTR(err);
+       }
+
        return kvm;
 }

mmu_notifier_unregister returns void and it's reliable.

The patch also adds a few needed but missing includes that would prevent
kernel to compile after these changes on non-x86 archs (x86 didn't need
them by luck).

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix mm/filemap_xip.c build]
[akpm@linux-foundation.org: fix mm/mmu_notifier.c build]
Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Kanoj Sarcar <kanojsarcar@yahoo.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Chris Wright <chrisw@redhat.com>
Cc: Marcelo Tosatti <marcelo@kvack.org>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Izik Eidus <izike@qumranet.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-28 16:30:21 -07:00
Sheng Yang
5fdbcb9dd1 KVM: VMX: Fix undefined beaviour of EPT after reload kvm-intel.ko
As well as move set base/mask ptes to vmx_init().

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-27 11:34:10 +03:00
Sheng Yang
5ec5726a16 KVM: VMX: Fix bypass_guest_pf enabling when disable EPT in module parameter
Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-27 11:34:10 +03:00
Marcelo Tosatti
c93cd3a588 KVM: task switch: translate guest segment limit to virt-extension byte granular field
If 'g' is one then limit is 4kb granular.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-27 11:34:10 +03:00
Avi Kivity
577bdc4966 KVM: Avoid instruction emulation when event delivery is pending
When an event (such as an interrupt) is injected, and the stack is
shadowed (and therefore write protected), the guest will exit.  The
current code will see that the stack is shadowed and emulate a few
instructions, each time postponing the injection.  Eventually the
injection may succeed, but at that time the guest may be unwilling
to accept the interrupt (for example, the TPR may have changed).

This occurs every once in a while during a Windows 2008 boot.

Fix by unshadowing the fault address if the fault was due to an event
injection.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-27 11:34:10 +03:00
Marcelo Tosatti
34198bf842 KVM: task switch: use seg regs provided by subarch instead of reading from GDT
There is no guarantee that the old TSS descriptor in the GDT contains
the proper base address. This is the case for Windows installation's
reboot-via-triplefault.

Use guest registers instead. Also translate the address properly.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-27 11:34:09 +03:00
Marcelo Tosatti
98899aa0e0 KVM: task switch: segment base is linear address
The segment base is always a linear address, so translate before
accessing guest memory.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-27 11:34:09 +03:00
Joerg Roedel
5f4cb662a0 KVM: SVM: allow enabling/disabling NPT by reloading only the architecture module
If NPT is enabled after loading both KVM modules on AMD and it should be
disabled, both KVM modules must be reloaded. If only the architecture module is
reloaded the behavior is undefined. With this patch it is possible to disable
NPT only by reloading the kvm_amd module.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-27 11:34:09 +03:00
Avi Kivity
722c05f219 KVM: MMU: Fix potential race setting upper shadow ptes on nonpae hosts
The direct mapped shadow code (used for real mode and two dimensional paging)
sets upper-level ptes using direct assignment rather than calling
set_shadow_pte().  A nonpae host will split this into two writes, which opens
up a race if another vcpu accesses the same memory area.

Fix by calling set_shadow_pte() instead of assigning directly.

Noticed by Izik Eidus.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:40 +03:00
Glauber Costa
2a7c5b8b55 KVM: x86 emulator: emulate clflush
If the guest issues a clflush in a mmio address, the instruction
can trap into the hypervisor. Currently, we do not decode clflush
properly, causing the guest to hang. This patch fixes this emulating
clflush (opcode 0f ae).

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:40 +03:00
Marcelo Tosatti
376c53c2b3 KVM: MMU: improve invalid shadow root page handling
Harden kvm_mmu_zap_page() against invalid root pages that
had been shadowed from memslots that are gone.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:40 +03:00
Marcelo Tosatti
34d4cb8fca KVM: MMU: nuke shadowed pgtable pages and ptes on memslot destruction
Flush the shadow mmu before removing regions to avoid stale entries.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:40 +03:00
Avi Kivity
d6e88aec07 KVM: Prefix some x86 low level function with kvm_, to avoid namespace issues
Fixes compilation with CONFIG_VMI enabled.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:39 +03:00
Ben-Ami Yassour
c65bbfa1d6 KVM: check injected pic irq within valid pic irqs
Check that an injected pic irq is between 0 and 15.

Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:39 +03:00
Mohammed Gamal
19fdfa0d13 KVM: x86 emulator: Fix HLT instruction
This patch fixes issue encountered with HLT instruction
under FreeDOS's HIMEM XMS Driver.

The HLT instruction jumped directly to the done label and
skips updating the EIP value, therefore causing the guest
to spin endlessly on the same instruction.

The patch changes the instruction so that it writes back
the updated EIP value.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:38 +03:00
Avi Kivity
ac9f6dc0db KVM: Apply the kernel sigmask to vcpus blocked due to being uninitialized
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:38 +03:00
Sheng Yang
4e1096d27f KVM: VMX: Add ept_sync_context in flush_tlb
Fix a potention issue caused by kvm_mmu_slot_remove_write_access(). The
old behavior don't sync EPT TLB with modified EPT entry, which result
in inconsistent content of EPT TLB and EPT table.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:38 +03:00
Marcelo Tosatti
5a4c928804 KVM: mmu_shrink: kvm_mmu_zap_page requires slots_lock to be held
kvm_mmu_zap_page() needs slots lock held (rmap_remove->gfn_to_memslot,
for example).

Since kvm_lock spinlock is held in mmu_shrink(), do a non-blocking
down_read_trylock().

Untested.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:38 +03:00
Joerg Roedel
0da1db75a2 KVM: SVM: fix suspend/resume support
On suspend the svm_hardware_disable function is called which frees all svm_data
variables. On resume they are not re-allocated. This patch removes the
deallocation of svm_data from the hardware_disable function to the
hardware_unsetup function which is not called on suspend.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:37 +03:00
Marcelo Tosatti
f8b78fa3d4 KVM: move slots_lock acquision down to vapic_exit
There is no need to grab slots_lock if the vapic_page will not
be touched.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:36 +03:00
Chris Lalancette
efa67e0d1f KVM: VMX: Fake emulate Intel perfctr MSRs
Older linux guests (in this case, 2.6.9) can attempt to
access the performance counter MSRs without a fixup section, and injecting
a GPF kills the guest.  Work around by allowing the guest to write those MSRs.

Tested by me on RHEL-4 i386 and x86_64 guests, as well as F-9 guests.

Signed-off-by: Chris Lalancette <clalance@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:36 +03:00
Sheng Yang
65267ea1b3 KVM: VMX: Fix a wrong usage of vmcs_config
The function ept_update_paging_mode_cr0() write to
CPU_BASED_VM_EXEC_CONTROL based on vmcs_config.cpu_based_exec_ctrl. That's
wrong because the variable may not consistent with the content in the
CPU_BASE_VM_EXEC_CONTROL MSR.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:36 +03:00
Avi Kivity
db475c39ec KVM: MMU: Fix printk format
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:35 +03:00
Avi Kivity
6ada8cca79 KVM: MMU: When debug is enabled, make it a run-time parameter
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:35 +03:00
Avi Kivity
7a5b56dfd3 KVM: x86 emulator: lazily evaluate segment registers
Instead of prefetching all segment bases before emulation, read them at the
last moment.  Since most of them are unneeded, we save some cycles on
Intel machines where this is a bit expensive.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:35 +03:00
Avi Kivity
0adc8675d6 KVM: x86 emulator: avoid segment base adjust for lea
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:34 +03:00
Avi Kivity
f5b4edcd52 KVM: x86 emulator: simplify rip relative decoding
rip relative decoding is relative to the instruction pointer of the next
instruction; by moving address adjustment until after decoding is complete,
we remove the need to determine the instruction size.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:34 +03:00
Avi Kivity
84411d85da KVM: x86 emulator: simplify r/m decoding
Consolidate the duplicated code when not in any special case.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:33 +03:00
Avi Kivity
dc71d0f162 KVM: x86 emulator: simplify sib decoding
Instead of using sparse switches, use simpler if/else sequences.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:33 +03:00
Avi Kivity
8684c0af0b KVM: x86 emulator: handle undecoded rex.b with r/m = 5 in certain cases
x86_64 does not decode rex.b in certain cases, where the r/m field = 5.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-07-20 12:42:33 +03:00