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commit 964b7aa0b040bdc6ec1c543ee620cda3f8b4c68a upstream.
In 64-bit mode, x86 instruction encoding allows us to use the low 8 bits
of any GPR as an 8-bit operand. In 32-bit mode, however, we can only use
the [abcd] registers. For which, GCC has the "q" constraint instead of
the less restrictive "r".
Also fix st->preempted, which is an input/output operand rather than an
input.
Fixes: 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <89bf72db1b859990355f9c40713a34e0d2d86c98.camel@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3e067fd8503d6205aa0c1c8f48f6b209c592d19c upstream.
When UBSAN is enabled, the code emitted for the call to guest_pv_has
includes a call to __ubsan_handle_load_invalid_value. objtool
complains that this call happens with UACCESS enabled; to avoid
the warning, pull the calls to user_access_begin into both arms
of the "if" statement, after the check for guest_pv_has.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 67f4b9969c305be515e47f809ecacfd86bd20a9c upstream.
Always check vmcs01's MSR bitmap when merging L0 and L1 bitmaps for L2,
and always update the relevant bits in vmcs02. This fixes two distinct,
but intertwined bugs related to dynamic MSR bitmap modifications.
The first issue is that KVM fails to enable MSR interception in vmcs02
for the FS/GS base MSRs if L1 first runs L2 with interception disabled,
and later enables interception.
The second issue is that KVM fails to honor userspace MSR filtering when
preparing vmcs02.
Fix both issues simultaneous as fixing only one of the issues (doesn't
matter which) would create a mess that no one should have to bisect.
Fixing only the first bug would exacerbate the MSR filtering issue as
userspace would see inconsistent behavior depending on the whims of L1.
Fixing only the second bug (MSR filtering) effectively requires fixing
the first, as the nVMX code only knows how to transition vmcs02's
bitmap from 1->0.
Move the various accessor/mutators that are currently buried in vmx.c
into vmx.h so that they can be shared by the nested code.
Fixes: 1a155254ff93 ("KVM: x86: Introduce MSR filtering")
Fixes: d69129b4e46a ("KVM: nVMX: Disable intercept for FS/GS base MSRs in vmcs02 when possible")
Cc: stable@vger.kernel.org
Cc: Alexander Graf <graf@amazon.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211109013047.2041518-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7dfbc624eb5726367900c8d86deff50836240361 upstream.
Check the current VMCS controls to determine if an MSR write will be
intercepted due to MSR bitmaps being disabled. In the nested VMX case,
KVM will disable MSR bitmaps in vmcs02 if they're disabled in vmcs12 or
if KVM can't map L1's bitmaps for whatever reason.
Note, the bad behavior is relatively benign in the current code base as
KVM sets all bits in vmcs02's MSR bitmap by default, clears bits if and
only if L0 KVM also disables interception of an MSR, and only uses the
buggy helper for MSR_IA32_SPEC_CTRL. Because KVM explicitly tests WRMSR
before disabling interception of MSR_IA32_SPEC_CTRL, the flawed check
will only result in KVM reading MSR_IA32_SPEC_CTRL from hardware when it
isn't strictly necessary.
Tag the fix for stable in case a future fix wants to use
msr_write_intercepted(), in which case a buggy implementation in older
kernels could prove subtly problematic.
Fixes: d28b387fb74d ("KVM/VMX: Allow direct access to MSR_IA32_SPEC_CTRL")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211109013047.2041518-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8b44b174f6aca815fc84c2038e4523ef8e32fabb upstream.
Move the core logic of SET_CPUID and SET_CPUID2 to a common helper, the
only difference between the two ioctls() is the format of the userspace
struct. A future fix will add yet more code to the core logic.
No functional change intended.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211105095101.5384-2-pdurrant@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7e2175ebd695f17860c5bd4ad7616cce12ed4591 upstream.
In commit b043138246a4 ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is
not missed") we switched to using a gfn_to_pfn_cache for accessing the
guest steal time structure in order to allow for an atomic xchg of the
preempted field. This has a couple of problems.
Firstly, kvm_map_gfn() doesn't work at all for IOMEM pages when the
atomic flag is set, which it is in kvm_steal_time_set_preempted(). So a
guest vCPU using an IOMEM page for its steal time would never have its
preempted field set.
Secondly, the gfn_to_pfn_cache is not invalidated in all cases where it
should have been. There are two stages to the GFN->PFN conversion;
first the GFN is converted to a userspace HVA, and then that HVA is
looked up in the process page tables to find the underlying host PFN.
Correct invalidation of the latter would require being hooked up to the
MMU notifiers, but that doesn't happen---so it just keeps mapping and
unmapping the *wrong* PFN after the userspace page tables change.
In the !IOMEM case at least the stale page *is* pinned all the time it's
cached, so it won't be freed and reused by anyone else while still
receiving the steal time updates. The map/unmap dance only takes care
of the KVM administrivia such as marking the page dirty.
Until the gfn_to_pfn cache handles the remapping automatically by
integrating with the MMU notifiers, we might as well not get a
kernel mapping of it, and use the perfectly serviceable userspace HVA
that we already have. We just need to implement the atomic xchg on
the userspace address with appropriate exception handling, which is
fairly trivial.
Cc: stable@vger.kernel.org
Fixes: b043138246a4 ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <3645b9b889dac6438394194bb5586a46b68d581f.camel@infradead.org>
[I didn't entirely agree with David's assessment of the
usefulness of the gfn_to_pfn cache, and integrated the outcome
of the discussion in the above commit message. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ec5a4919fa7b7d8c7a2af1c7e799b1fe4be84343 upstream.
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: bf9f6ac8d749 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 1e254d0d86a0f2efd4190a89d5204b37c18c6381 upstream.
This reverts commit 76b4f357d0e7d8f6f0013c733e6cba1773c266d3.
The commit has the wrong reasoning, as KVM_MAX_VCPU_ID is not defining the
maximum allowed vcpu-id as its name suggests, but the number of vcpu-ids.
So revert this patch again.
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210913135745.13944-2-jgross@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3d5e7a28b1ea2d603dea478e58e37ce75b9597ab upstream.
This is a new warning in clang top-of-tree (will be clang 14):
In file included from arch/x86/kvm/mmu/mmu.c:27:
arch/x86/kvm/mmu/spte.h:318:9: error: use of bitwise '|' with boolean operands [-Werror,-Wbitwise-instead-of-logical]
return __is_bad_mt_xwr(rsvd_check, spte) |
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
||
arch/x86/kvm/mmu/spte.h:318:9: note: cast one or both operands to int to silence this warning
The code is fine, but change it anyway to shut up this clever clogs
of a compiler.
Reported-by: torvic9@mailbox.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f3d1436d4bf8ced1c9a62a045d193a65567e1fcc upstream.
The Xen interrupt injection for event channels relies on accessing the
guest's vcpu_info structure in __kvm_xen_has_interrupt(), through a
gfn_to_hva_cache.
This requires the srcu lock to be held, which is mostly the case except
for this code path:
[ 11.822877] WARNING: suspicious RCU usage
[ 11.822965] -----------------------------
[ 11.823013] include/linux/kvm_host.h:664 suspicious rcu_dereference_check() usage!
[ 11.823131]
[ 11.823131] other info that might help us debug this:
[ 11.823131]
[ 11.823196]
[ 11.823196] rcu_scheduler_active = 2, debug_locks = 1
[ 11.823253] 1 lock held by dom:0/90:
[ 11.823292] #0: ffff998956ec8118 (&vcpu->mutex){+.+.}, at: kvm_vcpu_ioctl+0x85/0x680
[ 11.823379]
[ 11.823379] stack backtrace:
[ 11.823428] CPU: 2 PID: 90 Comm: dom:0 Kdump: loaded Not tainted 5.4.34+ #5
[ 11.823496] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[ 11.823612] Call Trace:
[ 11.823645] dump_stack+0x7a/0xa5
[ 11.823681] lockdep_rcu_suspicious+0xc5/0x100
[ 11.823726] __kvm_xen_has_interrupt+0x179/0x190
[ 11.823773] kvm_cpu_has_extint+0x6d/0x90
[ 11.823813] kvm_cpu_accept_dm_intr+0xd/0x40
[ 11.823853] kvm_vcpu_ready_for_interrupt_injection+0x20/0x30
< post_kvm_run_save() inlined here >
[ 11.823906] kvm_arch_vcpu_ioctl_run+0x135/0x6a0
[ 11.823947] kvm_vcpu_ioctl+0x263/0x680
Fixes: 40da8ccd724f ("KVM: x86/xen: Add event channel interrupt vector upcall")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: stable@vger.kernel.org
Message-Id: <606aaaf29fca3850a63aa4499826104e77a72346.camel@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9b0971ca7fc75daca80c0bb6c02e96059daea90a upstream.
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: 7ed9abfe8e9f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8228c77d8b56e3f735baf71fefb1b548c23691a7 upstream.
On the preemption path when updating a Xen guest's runstate times, this
lock is taken inside the scheduler rq->lock, which is a raw spinlock.
This was shown in a lockdep warning:
[ 89.138354] =============================
[ 89.138356] [ BUG: Invalid wait context ]
[ 89.138358] 5.15.0-rc5+ #834 Tainted: G S I E
[ 89.138360] -----------------------------
[ 89.138361] xen_shinfo_test/2575 is trying to lock:
[ 89.138363] ffffa34a0364efd8 (&kvm->arch.pvclock_gtod_sync_lock){....}-{3:3}, at: get_kvmclock_ns+0x1f/0x130 [kvm]
[ 89.138442] other info that might help us debug this:
[ 89.138444] context-{5:5}
[ 89.138445] 4 locks held by xen_shinfo_test/2575:
[ 89.138447] #0: ffff972bdc3b8108 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x77/0x6f0 [kvm]
[ 89.138483] #1: ffffa34a03662e90 (&kvm->srcu){....}-{0:0}, at: kvm_arch_vcpu_ioctl_run+0xdc/0x8b0 [kvm]
[ 89.138526] #2: ffff97331fdbac98 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0xff/0xbd0
[ 89.138534] #3: ffffa34a03662e90 (&kvm->srcu){....}-{0:0}, at: kvm_arch_vcpu_put+0x26/0x170 [kvm]
...
[ 89.138695] get_kvmclock_ns+0x1f/0x130 [kvm]
[ 89.138734] kvm_xen_update_runstate+0x14/0x90 [kvm]
[ 89.138783] kvm_xen_update_runstate_guest+0x15/0xd0 [kvm]
[ 89.138830] kvm_arch_vcpu_put+0xe6/0x170 [kvm]
[ 89.138870] kvm_sched_out+0x2f/0x40 [kvm]
[ 89.138900] __schedule+0x5de/0xbd0
Cc: stable@vger.kernel.org
Reported-by: syzbot+b282b65c2c68492df769@syzkaller.appspotmail.com
Fixes: 30b5c851af79 ("KVM: x86/xen: Add support for vCPU runstate information")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <1b02a06421c17993df337493a68ba923f3bd5c0f.camel@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0985dba842eaa391858972cfe2724c3c174a2827 upstream.
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: 40da8ccd724f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a3ca5281bb771d8103ea16f0a6a8a5df9a7fb4f3 upstream.
When updating mmu->pkru_mask, the value can only be added but it isn't
reset in advance. This will make mmu->pkru_mask keep the stale data.
Fix this issue.
Fixes: 2d344105f57c ("KVM, pkeys: introduce pkru_mask to cache conditions")
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Message-Id: <20211021071022.1140-1-chenyi.qiang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit baa1e5ca172ce7bf9554070139482dd7ea919528 upstream.
The refactoring in commit bb18a6777465 ("KVM: SEV: Acquire
vcpu mutex when updating VMSA") left behind the assignment to
svm->vcpu.arch.guest_state_protected; add it back.
Signed-off-by: Peter Gonda <pgonda@google.com>
[Delta between v2 and v3 of Peter's patch, which had already been
committed; the commit message is my own. - Paolo]
Fixes: bb18a6777465 ("KVM: SEV: Acquire vcpu mutex when updating VMSA")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6b5efc930bbc8c97e4a1fe2ccb9a6f286365a56d upstream.
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: 7ed9abfe8e9f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3b27de27183911d461afedf50c6fa30c59740c07 upstream.
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: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit de7cd3f6761f49bef044ec49493d88737a70f1a6 upstream.
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: 379a3c8ee444 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0d33b1baeb6ca7165d5ed4fdd1a8f969985e35b9 upstream.
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: 7ed9abfe8e9f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9f1ee7b169afbd10c3ad254220d1b37beb5798aa upstream.
The size of the GHCB scratch area is limited to 16 KiB (GHCB_SCRATCH_AREA_LIMIT),
so there is no need for it to be a u64. This fixes a build error on 32-bit
systems:
i686-linux-gnu-ld: arch/x86/kvm/svm/sev.o: in function `sev_es_string_io:
sev.c:(.text+0x110f): undefined reference to `__udivdi3'
Cc: stable@vger.kernel.org
Fixes: 019057bd73d1 ("KVM: SEV-ES: fix length of string I/O")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 95e16b4792b0429f1933872f743410f00e590c55 upstream.
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: 7ed9abfe8e9f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 019057bd73d1751fdfec41e43148baf3303d98f9 upstream.
The size of the data in the scratch buffer is not divided by the size of
each port I/O operation, so vcpu->arch.pio.count ends up being larger
than it should be by a factor of size.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4fa4b38dae6fc6a3695695add8c18fa8b6a05a1a upstream.
Make the diff a little nicer when we actually get to fixing
the bug. No functional change intended.
Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e9f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ea724ea420aac58b41bc822d1aed6940b136b78d upstream.
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: 7ed9abfe8e9f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b5998402e3de429b5e5f9bdea08ddf77c5fd661e upstream.
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: 7ed9abfe8e9f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c8c340a9b4149fe5caa433f3b62463a1c8e07a46 upstream.
Flush the destination page before invoking RECEIVE_UPDATE_DATA, as the
PSP encrypts the data with the guest's key when writing to guest memory.
If the target memory was not previously encrypted, the cache may contain
dirty, unecrypted data that will persist on non-coherent systems.
Fixes: 15fb7de1a7f5 ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command")
Cc: stable@vger.kernel.org
Cc: Peter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Masahiro Kozuka <masa.koz@kozuka.jp>
[sean: converted bug report to changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210914210951.2994260-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3a25dfa67fe40f3a2690af2c562e0947a78bd6a0 upstream.
Since commit c300ab9f08df ("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: c300ab9f08df ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit aee77e1169c1900fe4248dc186962e745b479d9e ]
In svm_clear_vintr we try to restore the virtual interrupt
injection that might be pending, but we fail to restore
the interrupt vector.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210914154825.104886-2-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e1fc1553cd78292ab3521c94c9dd6e3e70e606a1 ]
Intel PMU MSRs is in msrs_to_save_all[], so add AMD PMU MSRs to have a
consistent behavior between Intel and AMD when using KVM_GET_MSRS,
KVM_SET_MSRS or KVM_GET_MSR_INDEX_LIST.
We have to add legacy and new MSRs to handle guests running without
X86_FEATURE_PERFCTR_CORE.
Signed-off-by: Fares Mehanna <faresx@amazon.de>
Message-Id: <20210915133951.22389-1-faresx@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 37687c403a641f251cb2ef2e7830b88aa0647ba9 ]
When exiting SMM, pdpts are loaded again from the guest memory.
This fixes a theoretical bug, when exit from SMM triggers entry to the
nested guest which re-uses some of the migration
code which uses this flag as a workaround for a legacy userspace.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210913140954.165665-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit eb7511bf9182292ef1df1082d23039e856d1ddfb upstream.
Check the return of init_srcu_struct(), which can fail due to OOM, when
initializing the page track mechanism. Lack of checking leads to a NULL
pointer deref found by a modified syzkaller.
Reported-by: TCS Robot <tcs_robot@tencent.com>
Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com>
Message-Id: <1630636626-12262-1-git-send-email-tcs_kernel@tencent.com>
[Move the call towards the beginning of kvm_arch_init_vm. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 291073a566b2094c7192872cc0f17ce73d83cb76 ]
The recent change to make objtool aware of more symbol relocation types
(commit 24ff65257375: "objtool: Teach get_alt_entry() about more
relocation types") also added another check, and resulted in this
objtool warning when building kvm on x86:
arch/x86/kvm/emulate.o: warning: objtool: __ex_table+0x4: don't know how to handle reloc symbol type: kvm_fastop_exception
The reason seems to be that kvm_fastop_exception() is marked as a global
symbol, which causes the relocation to ke kept around for objtool. And
at the same time, the kvm_fastop_exception definition (which is done as
an inline asm statement) doesn't actually set the type of the global,
which then makes objtool unhappy.
The minimal fix is to just not mark kvm_fastop_exception as being a
global symbol. It's only used in that one compilation unit anyway, so
it was always pointless. That's how all the other local exception table
labels are done.
I'm not entirely happy about the kinds of games that the kvm code plays
with doing its own exception handling, and the fact that it confused
objtool is most definitely a symptom of the code being a bit too subtle
and ad-hoc. But at least this trivial one-liner makes objtool no longer
upset about what is going on.
Fixes: 24ff65257375 ("objtool: Teach get_alt_entry() about more relocation types")
Link: https://lore.kernel.org/lkml/CAHk-=wiZwq-0LknKhXN4M+T8jbxn_2i9mcKpO+OaBSSq_Eh7tg@mail.gmail.com/
Cc: Borislav Petkov <bp@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 5c49d1850ddd3240d20dc40b01f593e35a184f38 upstream.
When updating the host's mask for its MSR_IA32_TSX_CTRL user return entry,
clear the mask in the found uret MSR instead of vmx->guest_uret_msrs[i].
Modifying guest_uret_msrs directly is completely broken as 'i' does not
point at the MSR_IA32_TSX_CTRL entry. In fact, it's guaranteed to be an
out-of-bounds accesses as is always set to kvm_nr_uret_msrs in a prior
loop. By sheer dumb luck, the fallout is limited to "only" failing to
preserve the host's TSX_CTRL_CPUID_CLEAR. The out-of-bounds access is
benign as it's guaranteed to clear a bit in a guest MSR value, which are
always zero at vCPU creation on both x86-64 and i386.
Cc: stable@vger.kernel.org
Fixes: 8ea8b8d6f869 ("KVM: VMX: Use common x86's uret MSR list as the one true list")
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210926015545.281083-1-zhenzhong.duan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 24a996ade34d00deef5dee2c33aacd8fda91ec31 upstream.
Nested bus lock VM exits are not supported yet. If L2 triggers bus lock
VM exit, it will be directed to L1 VMM, which would cause unexpected
behavior. Therefore, handle L2's bus lock VM exits in L0 directly.
Fixes: fe6b6bc802b4 ("KVM: VMX: Enable bus lock VM exit")
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20210914095041.29764-1-chenyi.qiang@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f1815e0aa770f2127c5df31eb5c2f0e37b60fa77 upstream.
DECOMMISSION the current SEV context if binding an ASID fails after
RECEIVE_START. Per AMD's SEV API, RECEIVE_START generates a new guest
context and thus needs to be paired with DECOMMISSION:
The RECEIVE_START command is the only command other than the LAUNCH_START
command that generates a new guest context and guest handle.
The missing DECOMMISSION can result in subsequent SEV launch failures,
as the firmware leaks memory and might not able to allocate more SEV
guest contexts in the future.
Note, LAUNCH_START suffered the same bug, but was previously fixed by
commit 934002cd660b ("KVM: SVM: Call SEV Guest Decommission if ASID
binding fails").
Cc: Alper Gun <alpergun@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: David Rienjes <rientjes@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: John Allen <john.allen@amd.com>
Cc: Peter Gonda <pgonda@google.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vipin Sharma <vipinsh@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: Marc Orr <marcorr@google.com>
Acked-by: Brijesh Singh <brijesh.singh@amd.com>
Fixes: af43cbbf954b ("KVM: SVM: Add support for KVM_SEV_RECEIVE_START command")
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210912181815.3899316-1-mizhang@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5b92b6ca92b65bef811048c481e4446f4828500a upstream.
A mirrored SEV-ES VM will need to call KVM_SEV_LAUNCH_UPDATE_VMSA to
setup its vCPUs and have them measured, and their VMSAs encrypted. Without
this change, it is impossible to have mirror VMs as part of SEV-ES VMs.
Also allow the guest status check and debugging commands since they do
not change any guest state.
Signed-off-by: Peter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Nathan Tempelman <natet@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steve Rutherford <srutherford@google.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 54526d1fd593 ("KVM: x86: Support KVM VMs sharing SEV context", 2021-04-21)
Message-Id: <20210921150345.2221634-3-pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit bb18a677746543e7f5eeb478129c92cedb0f9658 upstream.
The update-VMSA ioctl touches data stored in struct kvm_vcpu, and
therefore should not be performed concurrently with any VCPU ioctl
that might cause KVM or the processor to use the same data.
Adds vcpu mutex guard to the VMSA updating code. Refactors out
__sev_launch_update_vmsa() function to deal with per vCPU parts
of sev_launch_update_vmsa().
Fixes: ad73109ae7ec ("KVM: SVM: Provide support to launch and run an SEV-ES guest")
Signed-off-by: Peter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: kvm@vger.kernel.org
Cc: stable@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Message-Id: <20210915171755.3773766-1-pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 50c038018d6be20361e8a2890262746a4ac5b11f upstream.
Require the target guest page to be writable when pinning memory for
RECEIVE_UPDATE_DATA. Per the SEV API, the PSP writes to guest memory:
The result is then encrypted with GCTX.VEK and written to the memory
pointed to by GUEST_PADDR field.
Fixes: 15fb7de1a7f5 ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command")
Cc: stable@vger.kernel.org
Cc: Peter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210914210951.2994260-2-seanjc@google.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f43c887cb7cb5b66c4167d40a4209027f5fdb5ce upstream.
For mirroring SEV-ES the mirror VM will need more then just the ASID.
The FD and the handle are required to all the mirror to call psp
commands. The mirror VM will need to call KVM_SEV_LAUNCH_UPDATE_VMSA to
setup its vCPUs' VMSAs for SEV-ES.
Signed-off-by: Peter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Nathan Tempelman <natet@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steve Rutherford <srutherford@google.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 54526d1fd593 ("KVM: x86: Support KVM VMs sharing SEV context", 2021-04-21)
Message-Id: <20210921150345.2221634-2-pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8d68bad6d869fae8f4d50ab6423538dec7da72d1 upstream.
Windows Server 2022 with Hyper-V role enabled failed to boot on KVM when
enlightened VMCS is advertised. Debugging revealed there are two exposed
secondary controls it is not happy with: SECONDARY_EXEC_ENABLE_VMFUNC and
SECONDARY_EXEC_SHADOW_VMCS. These controls are known to be unsupported,
as there are no corresponding fields in eVMCSv1 (see the comment above
EVMCS1_UNSUPPORTED_2NDEXEC definition).
Previously, commit 31de3d2500e4 ("x86/kvm/hyper-v: move VMX controls
sanitization out of nested_enable_evmcs()") introduced the required
filtering mechanism for VMX MSRs but for some reason put only known
to be problematic (and not full EVMCS1_UNSUPPORTED_* lists) controls
there.
Note, Windows Server 2022 seems to have gained some sanity check for VMX
MSRs: it doesn't even try to launch a guest when there's something it
doesn't like, nested_evmcs_check_controls() mechanism can't catch the
problem.
Let's be bold this time and instead of playing whack-a-mole just filter out
all unsupported controls from VMX MSRs.
Fixes: 31de3d2500e4 ("x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210907163530.110066-1-vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e8a747d0884e554a8c1872da6c8f680a4f893c6d upstream.
Check whether a CPUID entry's index is significant before checking for a
matching index to hack-a-fix an undefined behavior bug due to consuming
uninitialized data. RESET/INIT emulation uses kvm_cpuid() to retrieve
CPUID.0x1, which does _not_ have a significant index, and fails to
initialize the dummy variable that doubles as EBX/ECX/EDX output _and_
ECX, a.k.a. index, input.
Practically speaking, it's _extremely_ unlikely any compiler will yield
code that causes problems, as the compiler would need to inline the
kvm_cpuid() call to detect the uninitialized data, and intentionally hose
the kernel, e.g. insert ud2, instead of simply ignoring the result of
the index comparison.
Although the sketchy "dummy" pattern was introduced in SVM by commit
66f7b72e1171 ("KVM: x86: Make register state after reset conform to
specification"), it wasn't actually broken until commit 7ff6c0350315
("KVM: x86: Remove stateful CPUID handling") arbitrarily swapped the
order of operations such that "index" was checked before the significant
flag.
Avoid consuming uninitialized data by reverting to checking the flag
before the index purely so that the fix can be easily backported; the
offending RESET/INIT code has been refactored, moved, and consolidated
from vendor code to common x86 since the bug was introduced. A future
patch will directly address the bad RESET/INIT behavior.
The undefined behavior was detected by syzbot + KernelMemorySanitizer.
BUG: KMSAN: uninit-value in cpuid_entry2_find arch/x86/kvm/cpuid.c:68
BUG: KMSAN: uninit-value in kvm_find_cpuid_entry arch/x86/kvm/cpuid.c:1103
BUG: KMSAN: uninit-value in kvm_cpuid+0x456/0x28f0 arch/x86/kvm/cpuid.c:1183
cpuid_entry2_find arch/x86/kvm/cpuid.c:68 [inline]
kvm_find_cpuid_entry arch/x86/kvm/cpuid.c:1103 [inline]
kvm_cpuid+0x456/0x28f0 arch/x86/kvm/cpuid.c:1183
kvm_vcpu_reset+0x13fb/0x1c20 arch/x86/kvm/x86.c:10885
kvm_apic_accept_events+0x58f/0x8c0 arch/x86/kvm/lapic.c:2923
vcpu_enter_guest+0xfd2/0x6d80 arch/x86/kvm/x86.c:9534
vcpu_run+0x7f5/0x18d0 arch/x86/kvm/x86.c:9788
kvm_arch_vcpu_ioctl_run+0x245b/0x2d10 arch/x86/kvm/x86.c:10020
Local variable ----dummy@kvm_vcpu_reset created at:
kvm_vcpu_reset+0x1fb/0x1c20 arch/x86/kvm/x86.c:10812
kvm_apic_accept_events+0x58f/0x8c0 arch/x86/kvm/lapic.c:2923
Reported-by: syzbot+f3985126b746b3d59c9d@syzkaller.appspotmail.com
Reported-by: Alexander Potapenko <glider@google.com>
Fixes: 2a24be79b6b7 ("KVM: VMX: Set EDX at INIT with CPUID.0x1, Family-Model-Stepping")
Fixes: 7ff6c0350315 ("KVM: x86: Remove stateful CPUID handling")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20210929222426.1855730-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 03a6e84069d1870f5b3d360e64cb330b66f76dee upstream.
Explicitly zero the guest's CR3 and mark it available+dirty at RESET/INIT.
Per Intel's SDM and AMD's APM, CR3 is zeroed at both RESET and INIT. For
RESET, this is a nop as vcpu is zero-allocated. For INIT, the bug has
likely escaped notice because no firmware/kernel puts its page tables root
at PA=0, let alone relies on INIT to get the desired CR3 for such page
tables.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210921000303.400537-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit faf6b755629627f19feafa75b32e81cd7738f12d upstream.
These field correspond to features that we don't expose yet to L2
While currently there are no CVE worthy features in this field,
if AMD adds more features to this field, that could allow guest
escapes similar to CVE-2021-3653 and CVE-2021-3656.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210914154825.104886-6-mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2f9b68f57c6278c322793a06063181deded0ad69 upstream.
KASAN reports the following issue:
BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798
CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G X --------- ---
Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020
Call Trace:
dump_stack+0xa5/0xe6
print_address_description.constprop.0+0x18/0x130
? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
__kasan_report.cold+0x7f/0x114
? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
kasan_report+0x38/0x50
kasan_check_range+0xf5/0x1d0
kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm]
? kvm_arch_exit+0x110/0x110 [kvm]
? sched_clock+0x5/0x10
ioapic_write_indirect+0x59f/0x9e0 [kvm]
? static_obj+0xc0/0xc0
? __lock_acquired+0x1d2/0x8c0
? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm]
The problem appears to be that 'vcpu_bitmap' is allocated as a single long
on stack and it should really be KVM_MAX_VCPUS long. We also seem to clear
the lower 16 bits of it with bitmap_zero() for no particular reason (my
guess would be that 'bitmap' and 'vcpu_bitmap' variables in
kvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed
16-bit long, the later should accommodate all possible vCPUs).
Fixes: 7ee30bc132c6 ("KVM: x86: deliver KVM IOAPIC scan request to target vCPUs")
Fixes: 9a2ae9f6b6bb ("KVM: x86: Zero the IOAPIC scan request dest vCPUs bitmap")
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210827092516.1027264-7-vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f7782bb8d818d8f47c26b22079db10599922787a upstream.
Clear nested.pi_pending on nested VM-Enter even if L2 will run without
posted interrupts enabled. If nested.pi_pending is left set from a
previous L2, vmx_complete_nested_posted_interrupt() will pick up the
stale flag and exit to userspace with an "internal emulation error" due
the new L2 not having a valid nested.pi_desc.
Arguably, vmx_complete_nested_posted_interrupt() should first check for
posted interrupts being enabled, but it's also completely reasonable that
KVM wouldn't screw up a fundamental flag. Not to mention that the mere
existence of nested.pi_pending is a long-standing bug as KVM shouldn't
move the posted interrupt out of the IRR until it's actually processed,
e.g. KVM effectively drops an interrupt when it performs a nested VM-Exit
with a "pending" posted interrupt. Fixing the mess is a future problem.
Prior to vmx_complete_nested_posted_interrupt() interpreting a null PI
descriptor as an error, this was a benign bug as the null PI descriptor
effectively served as a check on PI not being enabled. Even then, the
new flow did not become problematic until KVM started checking the result
of kvm_check_nested_events().
Fixes: 705699a13994 ("KVM: nVMX: Enable nested posted interrupt processing")
Fixes: 966eefb89657 ("KVM: nVMX: Disable vmcs02 posted interrupts if vmcs12 PID isn't mappable")
Fixes: 47d3530f86c0 ("KVM: x86: Exit to userspace when kvm_check_nested_events fails")
Cc: stable@vger.kernel.org
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210810144526.2662272-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 81b4b56d4f8130bbb99cf4e2b48082e5b4cfccb9 upstream.
If we are emulating an invalid guest state, we don't have a correct
exit reason, and thus we shouldn't do anything in this function.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210826095750.1650467-2-mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 95b5a48c4f2b ("KVM: VMX: Handle NMIs, #MCs and async #PFs in common irqs-disabled fn", 2019-06-18)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 088acd23526647844aec1c39db4ad02552c86c7b upstream.
Factor in whether or not the old/new SPTEs are shadow-present when
adjusting the large page stats in the TDP MMU. A modified MMIO SPTE can
toggle the page size bit, as bit 7 is used to store the MMIO generation,
i.e. is_large_pte() can get a false positive when called on a MMIO SPTE.
Ditto for nuking SPTEs with REMOVED_SPTE, which sets bit 7 in its magic
value.
Opportunistically move the logic below the check to verify at least one
of the old/new SPTEs is shadow present.
Use is/was_leaf even though is/was_present would suffice. The code
generation is roughly equivalent since all flags need to be computed
prior to the code in question, and using the *_leaf flags will minimize
the diff in a future enhancement to account all pages, i.e. will change
the check to "is_leaf != was_leaf".
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Fixes: 1699f65c8b65 ("kvm/x86: Fix 'lpages' kvm stat for TDM MMU")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Message-Id: <20210803044607.599629-3-mizhang@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ec607a564f70519b340f7eb4cfc0f4a6b55285ac upstream.
This change started as a way to make kvm_mmu_hugepage_adjust a bit simpler,
but it does fix two bugs as well.
One bug is in zapping collapsible PTEs. If a large page size is
disallowed but not all of them, kvm_mmu_max_mapping_level will return the
host mapping level and the small PTEs will be zapped up to that level.
However, if e.g. 1GB are prohibited, we can still zap 4KB mapping and
preserve the 2MB ones. This can happen for example when NX huge pages
are in use.
The second would happen when userspace backs guest memory
with a 1gb hugepage but only assign a subset of the page to
the guest. 1gb pages would be disallowed by the memslot, but
not 2mb. kvm_mmu_max_mapping_level() would fall through to the
host_pfn_mapping_level() logic, see the 1gb hugepage, and map the whole
thing into the guest.
Fixes: 2f57b7051fe8 ("KVM: x86/mmu: Persist gfn_lpage_is_disallowed() to max_level")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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adjusted
commit d9130a2dfdd4b21736c91b818f87dbc0ccd1e757 upstream.
When MSR_IA32_TSC_ADJUST is written by guest due to TSC ADJUST feature
especially there's a big tsc warp (like a new vCPU is hot-added into VM
which has been up for a long time), tsc_offset is added by a large value
then go back to guest. This causes system time jump as tsc_timestamp is
not adjusted in the meantime and pvclock monotonic character.
To fix this, just notify kvm to update vCPU's guest time before back to
guest.
Cc: stable@vger.kernel.org
Signed-off-by: Zelin Deng <zelin.deng@linux.alibaba.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1619576521-81399-2-git-send-email-zelin.deng@linux.alibaba.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e7177339d7b5f9594b316842122b5fda9513d5e2 upstream.
Revert a misguided illegal GPA check when "translating" a non-nested GPA.
The check is woefully incomplete as it does not fill in @exception as
expected by all callers, which leads to KVM attempting to inject a bogus
exception, potentially exposing kernel stack information in the process.
WARNING: CPU: 0 PID: 8469 at arch/x86/kvm/x86.c:525 exception_type+0x98/0xb0 arch/x86/kvm/x86.c:525
CPU: 1 PID: 8469 Comm: syz-executor531 Not tainted 5.14.0-rc7-syzkaller #0
RIP: 0010:exception_type+0x98/0xb0 arch/x86/kvm/x86.c:525
Call Trace:
x86_emulate_instruction+0xef6/0x1460 arch/x86/kvm/x86.c:7853
kvm_mmu_page_fault+0x2f0/0x1810 arch/x86/kvm/mmu/mmu.c:5199
handle_ept_misconfig+0xdf/0x3e0 arch/x86/kvm/vmx/vmx.c:5336
__vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6021 [inline]
vmx_handle_exit+0x336/0x1800 arch/x86/kvm/vmx/vmx.c:6038
vcpu_enter_guest+0x2a1c/0x4430 arch/x86/kvm/x86.c:9712
vcpu_run arch/x86/kvm/x86.c:9779 [inline]
kvm_arch_vcpu_ioctl_run+0x47d/0x1b20 arch/x86/kvm/x86.c:10010
kvm_vcpu_ioctl+0x49e/0xe50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3652
The bug has escaped notice because practically speaking the GPA check is
useless. The GPA check in question only comes into play when KVM is
walking guest page tables (or "translating" CR3), and KVM already handles
illegal GPA checks by setting reserved bits in rsvd_bits_mask for each
PxE, or in the case of CR3 for loading PTDPTRs, manually checks for an
illegal CR3. This particular failure doesn't hit the existing reserved
bits checks because syzbot sets guest.MAXPHYADDR=1, and IA32 architecture
simply doesn't allow for such an absurd MAXPHYADDR, e.g. 32-bit paging
doesn't define any reserved PA bits checks, which KVM emulates by only
incorporating the reserved PA bits into the "high" bits, i.e. bits 63:32.
Simply remove the bogus check. There is zero meaningful value and no
architectural justification for supporting guest.MAXPHYADDR < 32, and
properly filling the exception would introduce non-trivial complexity.
This reverts commit ec7771ab471ba6a945350353617e2e3385d0e013.
Fixes: ec7771ab471b ("KVM: x86: mmu: Add guest physical address check in translate_gpa()")
Cc: stable@vger.kernel.org
Reported-by: syzbot+200c08e88ae818f849ce@syzkaller.appspotmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210831164224.1119728-2-seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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