RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1. Rather than dance around the issue of HF_SMM_MASK being set
when loading SMSTATE into architectural state, ideally RSM emulation
itself would be reworked to clear HF_SMM_MASK prior to loading non-SMM
architectural state.
Ostensibly, the only motivation for having HF_SMM_MASK set throughout
the loading of state from the SMRAM save state area is so that the
memory accesses from GET_SMSTATE() are tagged with role.smm. Load
all of the SMRAM save state area from guest memory at the beginning of
RSM emulation, and load state from the buffer instead of reading guest
memory one-by-one.
This paves the way for clearing HF_SMM_MASK prior to loading state,
and also aligns RSM with the enter_smm() behavior, which fills a
buffer and writes SMRAM save state in a single go.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM bases its memory usage limits on the total number of guest pages
across all memslots. However, those limits, and the calculations to
produce them, use 32 bit unsigned integers. This can result in overflow
if a VM has more guest pages that can be represented by a u32. As a
result of this overflow, KVM can use a low limit on the number of MMU
pages it will allocate. This makes KVM unable to map all of guest memory
at once, prompting spurious faults.
Tested: Ran all kvm-unit-tests on an Intel Haswell machine. This patch
introduced no new failures.
Signed-off-by: Ben Gardon <bgardon@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Most (all?) x86 platforms provide a port IO based reset mechanism, e.g.
OUT 92h or CF9h. Userspace may emulate said mechanism, i.e. reset a
vCPU in response to KVM_EXIT_IO, without explicitly announcing to KVM
that it is doing a reset, e.g. Qemu jams vCPU state and resumes running.
To avoid corruping %rip after such a reset, commit 0967b7bf1c ("KVM:
Skip pio instruction when it is emulated, not executed") changed the
behavior of PIO handlers, i.e. today's "fast" PIO handling to skip the
instruction prior to exiting to userspace. Full emulation doesn't need
such tricks becase re-emulating the instruction will naturally handle
%rip being changed to point at the reset vector.
Updating %rip prior to executing to userspace has several drawbacks:
- Userspace sees the wrong %rip on the exit, e.g. if PIO emulation
fails it will likely yell about the wrong address.
- Single step exits to userspace for are effectively dropped as
KVM_EXIT_DEBUG is overwritten with KVM_EXIT_IO.
- Behavior of PIO emulation is different depending on whether it
goes down the fast path or the slow path.
Rather than skip the PIO instruction before exiting to userspace,
snapshot the linear %rip and cancel PIO completion if the current
value does not match the snapshot. For a 64-bit vCPU, i.e. the most
common scenario, the snapshot and comparison has negligible overhead
as VMCS.GUEST_RIP will be cached regardless, i.e. there is no extra
VMREAD in this case.
All other alternatives to snapshotting the linear %rip that don't
rely on an explicit reset announcenment suffer from one corner case
or another. For example, canceling PIO completion on any write to
%rip fails if userspace does a save/restore of %rip, and attempting to
avoid that issue by canceling PIO only if %rip changed then fails if PIO
collides with the reset %rip. Attempting to zero in on the exact reset
vector won't work for APs, which means adding more hooks such as the
vCPU's MP_STATE, and so on and so forth.
Checking for a linear %rip match technically suffers from corner cases,
e.g. userspace could theoretically rewrite the underlying code page and
expect a different instruction to execute, or the guest hardcodes a PIO
reset at 0xfffffff0, but those are far, far outside of what can be
considered normal operation.
Fixes: 432baf60ee ("KVM: VMX: use kvm_fast_pio_in for handling IN I/O")
Cc: <stable@vger.kernel.org>
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The CPUID flag ARCH_CAPABILITIES is unconditioinally exposed to host
userspace for all x86 hosts, i.e. KVM advertises ARCH_CAPABILITIES
regardless of hardware support under the pretense that KVM fully
emulates MSR_IA32_ARCH_CAPABILITIES. Unfortunately, only VMX hosts
handle accesses to MSR_IA32_ARCH_CAPABILITIES (despite KVM_GET_MSRS
also reporting MSR_IA32_ARCH_CAPABILITIES for all hosts).
Move the MSR_IA32_ARCH_CAPABILITIES handling to common x86 code so
that it's emulated on AMD hosts.
Fixes: 1eaafe91a0 ("kvm: x86: IA32_ARCH_CAPABILITIES is always supported")
Cc: stable@vger.kernel.org
Reported-by: Xiaoyao Li <xiaoyao.li@linux.intel.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* nr_mmu_pages would be non-zero only if kvm->arch.n_requested_mmu_pages is
non-zero.
* nr_mmu_pages is always non-zero, since kvm_mmu_calculate_mmu_pages()
never return zero.
Based on these two reasons, we can merge the two *if* clause and use the
return value from kvm_mmu_calculate_mmu_pages() directly. This simplify
the code and also eliminate the possibility for reader to believe
nr_mmu_pages would be zero.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Errata#1096:
On a nested data page fault when CR.SMAP=1 and the guest data read
generates a SMAP violation, GuestInstrBytes field of the VMCB on a
VMEXIT will incorrectly return 0h instead the correct guest
instruction bytes .
Recommend Workaround:
To determine what instruction the guest was executing the hypervisor
will have to decode the instruction at the instruction pointer.
The recommended workaround can not be implemented for the SEV
guest because guest memory is encrypted with the guest specific key,
and instruction decoder will not be able to decode the instruction
bytes. If we hit this errata in the SEV guest then log the message
and request a guest shutdown.
Reported-by: Venkatesh Srinivas <venkateshs@google.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The cr4_pae flag is a bit of a misnomer, its purpose is really to track
whether the guest PTE that is being shadowed is a 4-byte entry or an
8-byte entry. Prior to supporting nested EPT, the size of the gpte was
reflected purely by CR4.PAE. KVM fudged things a bit for direct sptes,
but it was mostly harmless since the size of the gpte never mattered.
Now that a spte may be tracking an indirect EPT entry, relying on
CR4.PAE is wrong and ill-named.
For direct shadow pages, force the gpte_size to '1' as they are always
8-byte entries; EPT entries can only be 8-bytes and KVM always uses
8-byte entries for NPT and its identity map (when running with EPT but
not unrestricted guest).
Likewise, nested EPT entries are always 8-bytes. Nested EPT presents a
unique scenario as the size of the entries are not dictated by CR4.PAE,
but neither is the shadow page a direct map. To handle this scenario,
set cr0_wp=1 and smap_andnot_wp=1, an otherwise impossible combination,
to denote a nested EPT shadow page. Use the information to avoid
incorrectly zapping an unsync'd indirect page in __kvm_sync_page().
Providing a consistent and accurate gpte_size fixes a bug reported by
Vitaly where fast_cr3_switch() always fails when switching from L2 to
L1 as kvm_mmu_get_page() would force role.cr4_pae=0 for direct pages,
whereas kvm_calc_mmu_role_common() would set it according to CR4.PAE.
Fixes: 7dcd575520 ("x86/kvm/mmu: check if tdp/shadow MMU reconfiguration is needed")
Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
for 32-bit guests
s390: interrupt cleanup, introduction of the Guest Information Block,
preparation for processor subfunctions in cpu models
PPC: bug fixes and improvements, especially related to machine checks
and protection keys
x86: many, many cleanups, including removing a bunch of MMU code for
unnecessary optimizations; plus AVIC fixes.
Generic: memcg accounting
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"ARM:
- some cleanups
- direct physical timer assignment
- cache sanitization for 32-bit guests
s390:
- interrupt cleanup
- introduction of the Guest Information Block
- preparation for processor subfunctions in cpu models
PPC:
- bug fixes and improvements, especially related to machine checks
and protection keys
x86:
- many, many cleanups, including removing a bunch of MMU code for
unnecessary optimizations
- AVIC fixes
Generic:
- memcg accounting"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (147 commits)
kvm: vmx: fix formatting of a comment
KVM: doc: Document the life cycle of a VM and its resources
MAINTAINERS: Add KVM selftests to existing KVM entry
Revert "KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()"
KVM: PPC: Book3S: Add count cache flush parameters to kvmppc_get_cpu_char()
KVM: PPC: Fix compilation when KVM is not enabled
KVM: Minor cleanups for kvm_main.c
KVM: s390: add debug logging for cpu model subfunctions
KVM: s390: implement subfunction processor calls
arm64: KVM: Fix architecturally invalid reset value for FPEXC32_EL2
KVM: arm/arm64: Remove unused timer variable
KVM: PPC: Book3S: Improve KVM reference counting
KVM: PPC: Book3S HV: Fix build failure without IOMMU support
Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()"
x86: kvmguest: use TSC clocksource if invariant TSC is exposed
KVM: Never start grow vCPU halt_poll_ns from value below halt_poll_ns_grow_start
KVM: Expose the initial start value in grow_halt_poll_ns() as a module parameter
KVM: grow_halt_poll_ns() should never shrink vCPU halt_poll_ns
KVM: x86/mmu: Consolidate kvm_mmu_zap_all() and kvm_mmu_zap_mmio_sptes()
KVM: x86/mmu: WARN if zapping a MMIO spte results in zapping children
...
Previously, commit 7dcd575520 ("x86/kvm/mmu: check if tdp/shadow
MMU reconfiguration is needed") offered some optimization to avoid
the unnecessary reconfiguration. Yet one scenario is broken - when
cpuid changes VM's maximum physical address width, reconfiguration
is needed to reset the reserved bits. Also, the TDP may need to
reset its shadow_root_level when this value is changed.
To fix this, a new field, maxphyaddr, is introduced in the extended
role structure to keep track of the configured guest physical address
width.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 14c07ad89f ("x86/kvm/mmu: introduce guest_mmu") brought one subtle
change: previously, when switching back from L2 to L1, we were resetting
MMU hooks (like mmu->get_cr3()) in kvm_init_mmu() called from
nested_vmx_load_cr3() and now we do that in nested_ept_uninit_mmu_context()
when we re-target vcpu->arch.mmu pointer.
The change itself looks logical: if nested_ept_init_mmu_context() changes
something than nested_ept_uninit_mmu_context() restores it back. There is,
however, one thing: the following call chain:
nested_vmx_load_cr3()
kvm_mmu_new_cr3()
__kvm_mmu_new_cr3()
fast_cr3_switch()
cached_root_available()
now happens with MMU hooks pointing to the new MMU (root MMU in our case)
while previously it was happening with the old one. cached_root_available()
tries to stash current root but it is incorrect to read current CR3 with
mmu->get_cr3(), we need to use old_mmu->get_cr3() which in case we're
switching from L2 to L1 is guest_mmu. (BTW, in shadow page tables case this
is a non-issue because we don't switch MMU).
While we could've tried to guess that we're switching between MMUs and call
the right ->get_cr3() from cached_root_available() this seems to be overly
complicated. Instead, just stash the corresponding CR3 when setting
root_hpa and make cached_root_available() use the stashed value.
Fixes: 14c07ad89f ("x86/kvm/mmu: introduce guest_mmu")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove x86 KVM's fast invalidate mechanism, i.e. revert all patches
from the original series[1], now that all users of the fast invalidate
mechanism are gone.
This reverts commit 5304b8d37c.
[1] https://lkml.kernel.org/r/1369960590-14138-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com
Cc: Xiao Guangrong <guangrong.xiao@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Unwinding optimizations related to obsolete pages is a step towards
removing x86 KVM's fast invalidate mechanism, i.e. this is one part of
a revert all patches from the series that introduced the mechanism[1].
This reverts commit 365c886860.
[1] https://lkml.kernel.org/r/1369960590-14138-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com
Cc: Xiao Guangrong <guangrong.xiao@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Revert back to a dedicated (and slower) mechanism for handling the
scenario where all MMIO shadow PTEs need to be zapped due to overflowing
the MMIO generation number. The MMIO generation scenario is almost
literally a one-in-a-million occurrence, i.e. is not a performance
sensitive scenario.
Restoring kvm_mmu_zap_mmio_sptes() leaves VM teardown as the only user
of kvm_mmu_invalidate_zap_all_pages() and paves the way for removing
the fast invalidate mechanism altogether.
This reverts commit a8eca9dcc6.
Cc: Xiao Guangrong <guangrong.xiao@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove x86 KVM's fast invalidate mechanism, i.e. revert all patches
from the original series[1].
Though not explicitly stated, for all intents and purposes the fast
invalidate mechanism was added to speed up the scenario where removing
a memslot, e.g. as part of accessing reading PCI ROM, caused KVM to
flush all shadow entries[1]. Now that the memslot case flushes only
shadow entries belonging to the memslot, i.e. doesn't use the fast
invalidate mechanism, the only remaining usage of the mechanism are
when the VM is being destroyed and when the MMIO generation rolls
over.
When a VM is being destroyed, either there are no active vcpus, i.e.
there's no lock contention, or the VM has ungracefully terminated, in
which case we want to reclaim its pages as quickly as possible, i.e.
not release the MMU lock if there are still CPUs executing in the VM.
The MMIO generation scenario is almost literally a one-in-a-million
occurrence, i.e. is not a performance sensitive scenario.
Given that lock-breaking is not desirable (VM teardown) or irrelevant
(MMIO generation overflow), remove the fast invalidate mechanism to
simplify the code (a small amount) and to discourage future code from
zapping all pages as using such a big hammer should be a last restort.
This reverts commit f6f8adeef5.
[1] https://lkml.kernel.org/r/1369960590-14138-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com
Cc: Xiao Guangrong <guangrong.xiao@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_arch_memslots_updated() is at this point in time an x86-specific
hook for handling MMIO generation wraparound. x86 stashes 19 bits of
the memslots generation number in its MMIO sptes in order to avoid
full page fault walks for repeat faults on emulated MMIO addresses.
Because only 19 bits are used, wrapping the MMIO generation number is
possible, if unlikely. kvm_arch_memslots_updated() alerts x86 that
the generation has changed so that it can invalidate all MMIO sptes in
case the effective MMIO generation has wrapped so as to avoid using a
stale spte, e.g. a (very) old spte that was created with generation==0.
Given that the purpose of kvm_arch_memslots_updated() is to prevent
consuming stale entries, it needs to be called before the new generation
is propagated to memslots. Invalidating the MMIO sptes after updating
memslots means that there is a window where a vCPU could dereference
the new memslots generation, e.g. 0, and incorrectly reuse an old MMIO
spte that was created with (pre-wrap) generation==0.
Fixes: e59dbe09f8 ("KVM: Introduce kvm_arch_memslots_updated()")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Declaring the VCPU_REGS_* as enums allows for more robust C code, but it
prevents using the values in assembly files. Expliciting #define the
indices in an asm-friendly file to prepare for VMX moving its transition
code to a proper assembly file, but keep the enums for general usage.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
____kvm_handle_fault_on_reboot() provides a generic exception fixup
handler that is used to cleanly handle faults on VMX/SVM instructions
during reboot (or at least try to). If there isn't a reboot in
progress, ____kvm_handle_fault_on_reboot() treats any exception as
fatal to KVM and invokes kvm_spurious_fault(), which in turn generates
a BUG() to get a stack trace and die.
When it was originally added by commit 4ecac3fd6d ("KVM: Handle
virtualization instruction #UD faults during reboot"), the "call" to
kvm_spurious_fault() was handcoded as PUSH+JMP, where the PUSH'd value
is the RIP of the faulting instructing.
The PUSH+JMP trickery is necessary because the exception fixup handler
code lies outside of its associated function, e.g. right after the
function. An actual CALL from the .fixup code would show a slightly
bogus stack trace, e.g. an extra "random" function would be inserted
into the trace, as the return RIP on the stack would point to no known
function (and the unwinder will likely try to guess who owns the RIP).
Unfortunately, the JMP was replaced with a CALL when the macro was
reworked to not spin indefinitely during reboot (commit b7c4145ba2
"KVM: Don't spin on virt instruction faults during reboot"). This
causes the aforementioned behavior where a bogus function is inserted
into the stack trace, e.g. my builds like to blame free_kvm_area().
Revert the CALL back to a JMP. The changelog for commit b7c4145ba2
("KVM: Don't spin on virt instruction faults during reboot") contains
nothing that indicates the switch to CALL was deliberate. This is
backed up by the fact that the PUSH <insn RIP> was left intact.
Note that an alternative to the PUSH+JMP magic would be to JMP back
to the "real" code and CALL from there, but that would require adding
a JMP in the non-faulting path to avoid calling kvm_spurious_fault()
and would add no value, i.e. the stack trace would be the same.
Using CALL:
------------[ cut here ]------------
kernel BUG at /home/sean/go/src/kernel.org/linux/arch/x86/kvm/x86.c:356!
invalid opcode: 0000 [#1] SMP
CPU: 4 PID: 1057 Comm: qemu-system-x86 Not tainted 4.20.0-rc6+ #75
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:kvm_spurious_fault+0x5/0x10 [kvm]
Code: <0f> 0b 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 55 49 89 fd 41
RSP: 0018:ffffc900004bbcc8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffffffffffff
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888273fd8000 R08: 00000000000003e8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000784 R12: ffffc90000371fb0
R13: 0000000000000000 R14: 000000026d763cf4 R15: ffff888273fd8000
FS: 00007f3d69691700(0000) GS:ffff888277800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f89bc56fe0 CR3: 0000000271a5a001 CR4: 0000000000362ee0
Call Trace:
free_kvm_area+0x1044/0x43ea [kvm_intel]
? vmx_vcpu_run+0x156/0x630 [kvm_intel]
? kvm_arch_vcpu_ioctl_run+0x447/0x1a40 [kvm]
? kvm_vcpu_ioctl+0x368/0x5c0 [kvm]
? kvm_vcpu_ioctl+0x368/0x5c0 [kvm]
? __set_task_blocked+0x38/0x90
? __set_current_blocked+0x50/0x60
? __fpu__restore_sig+0x97/0x490
? do_vfs_ioctl+0xa1/0x620
? __x64_sys_futex+0x89/0x180
? ksys_ioctl+0x66/0x70
? __x64_sys_ioctl+0x16/0x20
? do_syscall_64+0x4f/0x100
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Modules linked in: vhost_net vhost tap kvm_intel kvm irqbypass bridge stp llc
---[ end trace 9775b14b123b1713 ]---
Using JMP:
------------[ cut here ]------------
kernel BUG at /home/sean/go/src/kernel.org/linux/arch/x86/kvm/x86.c:356!
invalid opcode: 0000 [#1] SMP
CPU: 6 PID: 1067 Comm: qemu-system-x86 Not tainted 4.20.0-rc6+ #75
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:kvm_spurious_fault+0x5/0x10 [kvm]
Code: <0f> 0b 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 55 49 89 fd 41
RSP: 0018:ffffc90000497cd0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffffffffffff
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88827058bd40 R08: 00000000000003e8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000784 R12: ffffc90000369fb0
R13: 0000000000000000 R14: 00000003c8fc6642 R15: ffff88827058bd40
FS: 00007f3d7219e700(0000) GS:ffff888277900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3d64001000 CR3: 0000000271c6b004 CR4: 0000000000362ee0
Call Trace:
vmx_vcpu_run+0x156/0x630 [kvm_intel]
? kvm_arch_vcpu_ioctl_run+0x447/0x1a40 [kvm]
? kvm_vcpu_ioctl+0x368/0x5c0 [kvm]
? kvm_vcpu_ioctl+0x368/0x5c0 [kvm]
? __set_task_blocked+0x38/0x90
? __set_current_blocked+0x50/0x60
? __fpu__restore_sig+0x97/0x490
? do_vfs_ioctl+0xa1/0x620
? __x64_sys_futex+0x89/0x180
? ksys_ioctl+0x66/0x70
? __x64_sys_ioctl+0x16/0x20
? do_syscall_64+0x4f/0x100
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Modules linked in: vhost_net vhost tap kvm_intel kvm irqbypass bridge stp llc
---[ end trace f9daedb85ab3ddba ]---
Fixes: b7c4145ba2 ("KVM: Don't spin on virt instruction faults during reboot")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The patch is to make kvm_set_spte_hva() return int and caller can
check return value to determine flush tlb or not.
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add flush range call back in the kvm_x86_ops and platform can use it
to register its associated function. The parameter "kvm_tlb_range"
accepts a single range and flush list which contains a list of ranges.
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Expose Intel Processor Trace to guest only when
the PT works in Host-Guest mode.
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Previously, the guest_fpu field was embedded in the kvm_vcpu_arch
struct. Unfortunately, the field is quite large, (e.g., 4352 bytes on my
current setup). This bloats the kvm_vcpu_arch struct for x86 into an
order 3 memory allocation, which can become a problem on overcommitted
machines. Thus, this patch moves the fpu state outside of the
kvm_vcpu_arch struct.
With this patch applied, the kvm_vcpu_arch struct is reduced to 15168
bytes for vmx on my setup when building the kernel with kvmconfig.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Marc Orr <marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Previously, x86's instantiation of 'struct kvm_vcpu_arch' added an fpu
field to save/restore fpu-related architectural state, which will differ
from kvm's fpu state. However, this is redundant to the 'struct fpu'
field, called fpu, embedded in the task struct, via the thread field.
Thus, this patch removes the user_fpu field from the kvm_vcpu_arch
struct and replaces it with the task struct's fpu field.
This change is significant because the fpu struct is actually quite
large. For example, on the system used to develop this patch, this
change reduces the size of the vcpu_vmx struct from 23680 bytes down to
19520 bytes, when building the kernel with kvmconfig. This reduction in
the size of the vcpu_vmx struct moves us closer to being able to
allocate the struct at order 2, rather than order 3.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Marc Orr <marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As a preparation to implementing Direct Mode for Hyper-V synthetic
timers switch to using stimer config definition from hyperv-tlfs.h.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The upcoming KVM_GET_SUPPORTED_HV_CPUID ioctl will need to return
Enlightened VMCS version in HYPERV_CPUID_NESTED_FEATURES.EAX when
it was enabled.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since commit e79f245dde ("X86/KVM: Properly update 'tsc_offset' to
represent the running guest"), vcpu->arch.tsc_offset meaning was
changed to always reflect the tsc_offset value set on active VMCS.
Regardless if vCPU is currently running L1 or L2.
However, above mentioned commit failed to also change
kvm_vcpu_write_tsc_offset() to set vcpu->arch.tsc_offset correctly.
This is because vmx_write_tsc_offset() could set the tsc_offset value
in active VMCS to given offset parameter *plus vmcs12->tsc_offset*.
However, kvm_vcpu_write_tsc_offset() just sets vcpu->arch.tsc_offset
to given offset parameter. Without taking into account the possible
addition of vmcs12->tsc_offset. (Same is true for SVM case).
Fix this issue by changing kvm_x86_ops->write_tsc_offset() to return
actually set tsc_offset in active VMCS and modify
kvm_vcpu_write_tsc_offset() to set returned value in
vcpu->arch.tsc_offset.
In addition, rename write_tsc_offset() callback to write_l1_tsc_offset()
to make it clear that it is meant to set L1 TSC offset.
Fixes: e79f245dde ("X86/KVM: Properly update 'tsc_offset' to represent the running guest")
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Leonid Shatz <leonid.shatz@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The per-VM capability KVM_CAP_EXCEPTION_PAYLOAD (to be introduced in a
later commit) adds the following fields to struct kvm_vcpu_events:
exception_has_payload, exception_payload, and exception.pending.
With this capability set, all of the details of vcpu->arch.exception,
including the payload for a pending exception, are reported to
userspace in response to KVM_GET_VCPU_EVENTS.
With this capability clear, the original ABI is preserved, and the
exception.injected field is set for either pending or injected
exceptions.
When userspace calls KVM_SET_VCPU_EVENTS with
KVM_CAP_EXCEPTION_PAYLOAD clear, exception.injected is no longer
translated to exception.pending. KVM_SET_VCPU_EVENTS can now only
establish a pending exception when KVM_CAP_EXCEPTION_PAYLOAD is set.
Reported-by: Jim Mattson <jmattson@google.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The payload associated with a #PF exception is the linear address of
the fault to be loaded into CR2 when the fault is delivered. The
payload associated with a #DB exception is a mask of the DR6 bits to
be set (or in the case of DR6.RTM, cleared) when the fault is
delivered. Add fields has_payload and payload to kvm_queued_exception
to track payloads for pending exceptions.
The new fields are introduced here, but for now, they are just cleared.
Reported-by: Jim Mattson <jmattson@google.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Enlightened VMCS is opt-in. The current version does not contain all
fields supported by nested VMX so we must not advertise the
corresponding VMX features if enlightened VMCS is enabled.
Userspace is given the enlightened VMCS version supported by KVM as
part of enabling KVM_CAP_HYPERV_ENLIGHTENED_VMCS. The version is to
be advertised to the nested hypervisor, currently done via a cpuid
leaf for Hyper-V.
Suggested-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
MMU reconfiguration in init_kvm_tdp_mmu()/kvm_init_shadow_mmu() can be
avoided if the source data used to configure it didn't change; enhance
MMU extended role with the required fields and consolidate common code in
kvm_calc_mmu_role_common().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
MMU re-initialization is expensive, in particular,
update_permission_bitmask() and update_pkru_bitmask() are.
Cache the data used to setup shadow EPT MMU and avoid full re-init when
it is unchanged.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In preparation to MMU reconfiguration avoidance we need a space to
cache source data. As this partially intersects with kvm_mmu_page_role,
create 64bit sized union kvm_mmu_role holding both base and extended data.
No functional change.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Just inline the contents into the sole caller, kvm_init_mmu is now
public.
Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
When EPT is used for nested guest we need to re-init MMU as shadow
EPT MMU (nested_ept_init_mmu_context() does that). When we return back
from L2 to L1 kvm_mmu_reset_context() in nested_vmx_load_cr3() resets
MMU back to normal TDP mode. Add a special 'guest_mmu' so we can use
separate root caches; the improved hit rate is not very important for
single vCPU performance, but it avoids contention on the mmu_lock for
many vCPUs.
On the nested CPUID benchmark, with 16 vCPUs, an L2->L1->L2 vmexit
goes from 42k to 26k cycles.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add an option to specify which MMU root we want to free. This will
be used when nested and non-nested MMUs for L1 are split.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
As a preparation to full MMU split between L1 and L2 make vcpu->arch.mmu
a pointer to the currently used mmu. For now, this is always
vcpu->arch.root_mmu. No functional change.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Regardless of whether your TLB is lush or not it still needs flushing.
Reported-by: Roman Kagan <rkagan@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In most common cases VP index of a vcpu matches its vcpu index. Userspace
is, however, free to set any mapping it wishes and we need to account for
that when we need to find a vCPU with a particular VP index. To keep search
algorithms optimal in both cases introduce 'num_mismatched_vp_indexes'
counter showing how many vCPUs with mismatching VP index we have. In case
the counter is zero we can assume vp_index == vcpu_idx.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, there are two definitions related to huge page, but a little bit
far from each other and seems loosely connected:
* KVM_NR_PAGE_SIZES defines the number of different size a page could map
* PT_MAX_HUGEPAGE_LEVEL means the maximum level of huge page
The number of different size a page could map equals the maximum level
of huge page, which is implied by current definition.
While current implementation may not be kind to readers and further
developers:
* KVM_NR_PAGE_SIZES looks like a stand alone definition at first sight
* in case we need to support more level, two places need to change
This patch tries to make these two definition more close, so that reader
and developer would feel more comfortable to manipulate.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On a 64bits machine, struct is naturally aligned with 8 bytes. Since
kvm_mmu_page member *unsync* and *role* are less then 4 bytes, we can
rearrange the sequence to compace the struct.
As the comment shows, *role* and *gfn* are used to key the shadow page. In
order to keep the comment valid, this patch moves the *unsync* up and
exchange the position of *role* and *gfn*.
From /proc/slabinfo, it shows the size of kvm_mmu_page is 8 bytes less and
with one more object per slap after applying this patch.
# name <active_objs> <num_objs> <objsize> <objperslab>
kvm_mmu_page_header 0 0 168 24
kvm_mmu_page_header 0 0 160 25
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
According to volume 3 of the SDM, bits 63:15 and 12:4 of the exit
qualification field for debug exceptions are reserved (cleared to
0). However, the SDM is incorrect about bit 16 (corresponding to
DR6.RTM). This bit should be set if a debug exception (#DB) or a
breakpoint exception (#BP) occurred inside an RTM region while
advanced debugging of RTM transactional regions was enabled. Note that
this is the opposite of DR6.RTM, which "indicates (when clear) that a
debug exception (#DB) or breakpoint exception (#BP) occurred inside an
RTM region while advanced debugging of RTM transactional regions was
enabled."
There is still an issue with stale DR6 bits potentially being
misreported for the current debug exception. DR6 should not have been
modified before vectoring the #DB exception, and the "new DR6 bits"
should be available somewhere, but it was and they aren't.
Fixes: b96fb43977 ("KVM: nVMX: fixes to nested virt interrupt injection")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add KVM_CAP_MSR_PLATFORM_INFO so that userspace can disable guest access
to reads of MSR_PLATFORM_INFO.
Disabling access to reads of this MSR gives userspace the control to "expose"
this platform-dependent information to guests in a clear way. As it exists
today, guests that read this MSR would get unpopulated information if userspace
hadn't already set it (and prior to this patch series, only the CPUID faulting
information could have been populated). This existing interface could be
confusing if guests don't handle the potential for incorrect/incomplete
information gracefully (e.g. zero reported for base frequency).
Signed-off-by: Drew Schmitt <dasch@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In case L1 do not intercept L2 HLT or enter L2 in HLT activity-state,
it is possible for a vCPU to be blocked while it is in guest-mode.
According to Intel SDM 26.6.5 Interrupt-Window Exiting and
Virtual-Interrupt Delivery: "These events wake the logical processor
if it just entered the HLT state because of a VM entry".
Therefore, if L1 enters L2 in HLT activity-state and L2 has a pending
deliverable interrupt in vmcs12->guest_intr_status.RVI, then the vCPU
should be waken from the HLT state and injected with the interrupt.
In addition, if while the vCPU is blocked (while it is in guest-mode),
it receives a nested posted-interrupt, then the vCPU should also be
waken and injected with the posted interrupt.
To handle these cases, this patch enhances kvm_vcpu_has_events() to also
check if there is a pending interrupt in L2 virtual APICv provided by
L1. That is, it evaluates if there is a pending virtual interrupt for L2
by checking RVI[7:4] > VPPR[7:4] as specified in Intel SDM 29.2.1
Evaluation of Pending Interrupts.
Note that this also handles the case of nested posted-interrupt by the
fact RVI is updated in vmx_complete_nested_posted_interrupt() which is
called from kvm_vcpu_check_block() -> kvm_arch_vcpu_runnable() ->
kvm_vcpu_running() -> vmx_check_nested_events() ->
vmx_complete_nested_posted_interrupt().
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A VMX preemption timer value of '0' is guaranteed to cause a VMExit
prior to the CPU executing any instructions in the guest. Use the
preemption timer (if it's supported) to trigger immediate VMExit
in place of the current method of sending a self-IPI. This ensures
that pending VMExit injection to L1 occurs prior to executing any
instructions in the guest (regardless of nesting level).
When deferring VMExit injection, KVM generates an immediate VMExit
from the (possibly nested) guest by sending itself an IPI. Because
hardware interrupts are blocked prior to VMEnter and are unblocked
(in hardware) after VMEnter, this results in taking a VMExit(INTR)
before any guest instruction is executed. But, as this approach
relies on the IPI being received before VMEnter executes, it only
works as intended when KVM is running as L0. Because there are no
architectural guarantees regarding when IPIs are delivered, when
running nested the INTR may "arrive" long after L2 is running e.g.
L0 KVM doesn't force an immediate switch to L1 to deliver an INTR.
For the most part, this unintended delay is not an issue since the
events being injected to L1 also do not have architectural guarantees
regarding their timing. The notable exception is the VMX preemption
timer[1], which is architecturally guaranteed to cause a VMExit prior
to executing any instructions in the guest if the timer value is '0'
at VMEnter. Specifically, the delay in injecting the VMExit causes
the preemption timer KVM unit test to fail when run in a nested guest.
Note: this approach is viable even on CPUs with a broken preemption
timer, as broken in this context only means the timer counts at the
wrong rate. There are no known errata affecting timer value of '0'.
[1] I/O SMIs also have guarantees on when they arrive, but I have
no idea if/how those are emulated in KVM.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Use a hook for SVM instead of leaving the default in x86.c - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Dan Carpenter reported that the untrusted data returns from kvm_register_read()
results in the following static checker warning:
arch/x86/kvm/lapic.c:576 kvm_pv_send_ipi()
error: buffer underflow 'map->phys_map' 's32min-s32max'
KVM guest can easily trigger this by executing the following assembly sequence
in Ring0:
mov $10, %rax
mov $0xFFFFFFFF, %rbx
mov $0xFFFFFFFF, %rdx
mov $0, %rsi
vmcall
As this will cause KVM to execute the following code-path:
vmx_handle_exit() -> handle_vmcall() -> kvm_emulate_hypercall() -> kvm_pv_send_ipi()
which will reach out-of-bounds access.
This patch fixes it by adding a check to kvm_pv_send_ipi() against map->max_apic_id,
ignoring destinations that are not present and delivering the rest. We also check
whether or not map->phys_map[min + i] is NULL since the max_apic_id is set to the
max apic id, some phys_map maybe NULL when apic id is sparse, especially kvm
unconditionally set max_apic_id to 255 to reserve enough space for any xAPIC ID.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
[Add second "if (min > map->max_apic_id)" to complete the fix. -Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
- Fix a VFP corruption in 32-bit guest
- Add missing cache invalidation for CoW pages
- Two small cleanups
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Merge tag 'kvm-arm-fixes-for-v4.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm
Fixes for KVM/ARM for Linux v4.19 v2:
- Fix a VFP corruption in 32-bit guest
- Add missing cache invalidation for CoW pages
- Two small cleanups
kvm_unmap_hva is long gone, and we only have kvm_unmap_hva_range to
deal with. Drop the now obsolete code.
Fixes: fb1522e099 ("KVM: update to new mmu_notifier semantic v2")
Cc: James Hogan <jhogan@kernel.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Allowing x86_emulate_instruction() to be called directly has led to
subtle bugs being introduced, e.g. not setting EMULTYPE_NO_REEXECUTE
in the emulation type. While most of the blame lies on re-execute
being opt-out, exporting x86_emulate_instruction() also exposes its
cr2 parameter, which may have contributed to commit d391f12070
("x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO
when running nested") using x86_emulate_instruction() instead of
emulate_instruction() because "hey, I have a cr2!", which in turn
introduced its EMULTYPE_NO_REEXECUTE bug.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Lack of the kvm_ prefix gives the impression that it's a VMX or SVM
specific function, and there's no conflict that prevents adding the
kvm_ prefix.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
retry_instruction() and reexecute_instruction() are a package deal,
i.e. there is no scenario where one is allowed and the other is not.
Merge their controlling emulation type flags to enforce this in code.
Name the combined flag EMULTYPE_ALLOW_RETRY to make it abundantly
clear that we are allowing re{try,execute} to occur, as opposed to
explicitly requesting retry of a previously failed instruction.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Re-execution of an instruction after emulation decode failure is
intended to be used only when emulating shadow page accesses. Invert
the flag to make allowing re-execution opt-in since that behavior is
by far in the minority.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Sean Christopherson