Move kvm_arch_flush_remote_tlbs_memslot() from x86.c to mmu.c in
preparation for calling kvm_flush_remote_tlbs_with_address() instead of
kvm_flush_remote_tlbs(). The with_address() variant is statically
defined in mmu.c, arguably kvm_arch_flush_remote_tlbs_memslot() belongs
in mmu.c anyways, and defining kvm_arch_flush_remote_tlbs_memslot() in
mmu.c will allow the compiler to inline said function when a future
patch consolidates open coded variants of the function.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Refactor memslot handling to treat the number of used slots as the de
facto size of the memslot array, e.g. return NULL from id_to_memslot()
when an invalid index is provided instead of relying on npages==0 to
detect an invalid memslot. Rework the sorting and walking of memslots
in advance of dynamically sizing memslots to aid bisection and debug,
e.g. with luck, a bug in the refactoring will bisect here and/or hit a
WARN instead of randomly corrupting memory.
Alternatively, a global null/invalid memslot could be returned, i.e. so
callers of id_to_memslot() don't have to explicitly check for a NULL
memslot, but that approach runs the risk of introducing difficult-to-
debug issues, e.g. if the global null slot is modified. Constifying
the return from id_to_memslot() to combat such issues is possible, but
would require a massive refactoring of arch specific code and would
still be susceptible to casting shenanigans.
Add function comments to update_memslots() and search_memslots() to
explicitly (and loudly) state how memslots are sorted.
Opportunistically stuff @hva with a non-canonical value when deleting a
private memslot on x86 to detect bogus usage of the freed slot.
No functional change intended.
Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the implementations of KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG
for CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT into common KVM code.
The arch specific implemenations are extremely similar, differing
only in whether the dirty log needs to be sync'd from hardware (x86)
and how the TLBs are flushed. Add new arch hooks to handle sync
and TLB flush; the sync will also be used for non-generic dirty log
support in a future patch (s390).
The ulterior motive for providing a common implementation is to
eliminate the dependency between arch and common code with respect to
the memslot referenced by the dirty log, i.e. to make it obvious in the
code that the validity of the memslot is guaranteed, as a future patch
will rework memslot handling such that id_to_memslot() can return NULL.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that all callers of kvm_free_memslot() pass NULL for @dont, remove
the param from the top-level routine and all arch's implementations.
No functional change intended.
Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Explicitly free the metadata arrays (stored in slot->arch) in the old
memslot structure when moving the memslot's base gfn is committed. This
eliminates x86's dependency on kvm_free_memslot() being called when a
memslot move is committed, and paves the way for removing the funky code
in kvm_free_memslot() that conditionally frees structures based on its
@dont param.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Drop the "const" attribute from @old in kvm_arch_commit_memory_region()
to allow arch specific code to free arch specific resources in the old
memslot without having to cast away the attribute. Freeing resources in
kvm_arch_commit_memory_region() paves the way for simplifying
kvm_free_memslot() by eliminating the last usage of its @dont param.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove kvm_arch_create_memslot() now that all arch implementations are
effectively nops. Removing kvm_arch_create_memslot() eliminates the
possibility for arch specific code to allocate memory prior to setting
a memslot, which sets the stage for simplifying kvm_free_memslot().
Cc: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Allocate the various metadata structures associated with a new memslot
during kvm_arch_prepare_memory_region(), which paves the way for
removing kvm_arch_create_memslot() altogether. Moving x86's memory
allocation only changes the order of kernel memory allocations between
x86 and common KVM code.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reallocate a rmap array and recalcuate large page compatibility when
moving an existing memslot to correctly handle the alignment properties
of the new memslot. The number of rmap entries required at each level
is dependent on the alignment of the memslot's base gfn with respect to
that level, e.g. moving a large-page aligned memslot so that it becomes
unaligned will increase the number of rmap entries needed at the now
unaligned level.
Not updating the rmap array is the most obvious bug, as KVM accesses
garbage data beyond the end of the rmap. KVM interprets the bad data as
pointers, leading to non-canonical #GPs, unexpected #PFs, etc...
general protection fault: 0000 [#1] SMP
CPU: 0 PID: 1909 Comm: move_memory_reg Not tainted 5.4.0-rc7+ #139
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:rmap_get_first+0x37/0x50 [kvm]
Code: <48> 8b 3b 48 85 ff 74 ec e8 6c f4 ff ff 85 c0 74 e3 48 89 d8 5b c3
RSP: 0018:ffffc9000021bbc8 EFLAGS: 00010246
RAX: ffff00617461642e RBX: ffff00617461642e RCX: 0000000000000012
RDX: ffff88827400f568 RSI: ffffc9000021bbe0 RDI: ffff88827400f570
RBP: 0010000000000000 R08: ffffc9000021bd00 R09: ffffc9000021bda8
R10: ffffc9000021bc48 R11: 0000000000000000 R12: 0030000000000000
R13: 0000000000000000 R14: ffff88827427d700 R15: ffffc9000021bce8
FS: 00007f7eda014700(0000) GS:ffff888277a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7ed9216ff8 CR3: 0000000274391003 CR4: 0000000000162eb0
Call Trace:
kvm_mmu_slot_set_dirty+0xa1/0x150 [kvm]
__kvm_set_memory_region.part.64+0x559/0x960 [kvm]
kvm_set_memory_region+0x45/0x60 [kvm]
kvm_vm_ioctl+0x30f/0x920 [kvm]
do_vfs_ioctl+0xa1/0x620
ksys_ioctl+0x66/0x70
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x4c/0x170
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f7ed9911f47
Code: <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 21 6f 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc00937498 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000001ab0010 RCX: 00007f7ed9911f47
RDX: 0000000001ab1350 RSI: 000000004020ae46 RDI: 0000000000000004
RBP: 000000000000000a R08: 0000000000000000 R09: 00007f7ed9214700
R10: 00007f7ed92149d0 R11: 0000000000000246 R12: 00000000bffff000
R13: 0000000000000003 R14: 00007f7ed9215000 R15: 0000000000000000
Modules linked in: kvm_intel kvm irqbypass
---[ end trace 0c5f570b3358ca89 ]---
The disallow_lpage tracking is more subtle. Failure to update results
in KVM creating large pages when it shouldn't, either due to stale data
or again due to indexing beyond the end of the metadata arrays, which
can lead to memory corruption and/or leaking data to guest/userspace.
Note, the arrays for the old memslot are freed by the unconditional call
to kvm_free_memslot() in __kvm_set_memory_region().
Fixes: 05da45583d ("KVM: MMU: large page support")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the GPA tracking into the emulator context now that the context is
guaranteed to be initialized via __init_emulate_ctxt() prior to
dereferencing gpa_{available,val}, i.e. now that seeing a stale
gpa_available will also trigger a WARN due to an invalid context.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a new emulation type flag to explicitly mark emulation related to a
page fault. Move the propation of the GPA into the emulator from the
page fault handler into x86_emulate_instruction, using EMULTYPE_PF as an
indicator that cr2 is valid. Similarly, don't propagate cr2 into the
exception.address when it's *not* valid.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In older version of systemd(219), at boot time, udevadm is called with :
/usr/bin/udevadm trigger --type=devices --action=add"
This program generates an echo "add" in /sys/devices/system/cpu/cpu<x>/uevent,
leading to the "kvm: disabled by bios" message in case of your Bios disabled
the virtualization extensions.
On a modern system running up to 256 CPU threads, this pollutes the Kernel logs.
This patch offers to ratelimit this message to avoid any userspace program triggering
this uevent printing this message too often.
This patch is only a workaround but greatly reduce the pollution without
breaking the current behavior of printing a message if some try to instantiate
KVM on a system that doesn't support it.
Note that recent versions of systemd (>239) do not have trigger this behavior.
This patch will be useful at least for some using older systemd with recent Kernels.
Signed-off-by: Erwan Velu <e.velu@criteo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
struct cpufreq_policy is quite big and it is not a good idea
to allocate one on the stack. Just use cpufreq_cpu_get and
cpufreq_cpu_put which is even simpler.
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since commit 5f3d45e7f2 ("kvm/x86: add support for
MONITOR_TRAP_FLAG"), KVM has allowed an L1 guest to use the monitor trap
flag processor-based execution control for its L2 guest. KVM simply
forwards any MTF VM-exits to the L1 guest, which works for normal
instruction execution.
However, when KVM needs to emulate an instruction on the behalf of an L2
guest, the monitor trap flag is not emulated. Add the necessary logic to
kvm_skip_emulated_instruction() to synthesize an MTF VM-exit to L1 upon
instruction emulation for L2.
Fixes: 5f3d45e7f2 ("kvm/x86: add support for MONITOR_TRAP_FLAG")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The check cpu->hv_clock.system_time < 0 is redundant since system_time
is a u64 and hence can never be less than zero. But what was actually
meant is to check that the result is positive, since kernel_ns and
v->kvm->arch.kvmclock_offset are both s64.
Reported-by: Colin King <colin.king@canonical.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Addresses-Coverity: ("Macro compares unsigned to 0")
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Wrap calls to ->page_fault() with a small shim to directly invoke the
TDP fault handler when the kernel is using retpolines and TDP is being
used. Single out the TDP fault handler and annotate the TDP path as
likely to coerce the compiler into preferring it over the indirect
function call.
Rename tdp_page_fault() to kvm_tdp_page_fault(), as it's exposed outside
of mmu.c to allow inlining the shim.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The KVM_REQ_EVENT request is already made in kvm_set_rflags(). We should
not make it again.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM allows the deferral of exception payloads when a vCPU is in guest
mode to allow the L1 hypervisor to intercept certain events (#PF, #DB)
before register state has been modified. However, this behavior is
incompatible with the KVM_{GET,SET}_VCPU_EVENTS ABI, as userspace
expects register state to have been immediately modified. Userspace may
opt-in for the payload deferral behavior with the
KVM_CAP_EXCEPTION_PAYLOAD per-VM capability. As such,
kvm_multiple_exception() will immediately manipulate guest registers if
the capability hasn't been requested.
Since the deferral is only necessary if a userspace ioctl were to be
serviced at the same as a payload bearing exception is recognized, this
behavior can be relaxed. Instead, opportunistically defer the payload
from kvm_multiple_exception() and deliver the payload before completing
a KVM_GET_VCPU_EVENTS ioctl.
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM defines the #DB payload as compatible with the 'pending debug
exceptions' field under VMX, not DR6. Mask off bit 12 when applying the
payload to DR6, as it is reserved on DR6 but not the 'pending debug
exceptions' field.
Fixes: f10c729ff9 ("kvm: vmx: Defer setting of DR6 until #DB delivery")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Re-add code to mark CR4.UMIP as reserved if UMIP is not supported by the
host. The UMIP handling was unintentionally dropped during a recent
refactoring.
Not flagging CR4.UMIP allows the guest to set its CR4.UMIP regardless of
host support or userspace desires. On CPUs with UMIP support, including
emulated UMIP, this allows the guest to enable UMIP against the wishes
of the userspace VMM. On CPUs without any form of UMIP, this results in
a failed VM-Enter due to invalid guest state.
Fixes: 345599f9a2 ("KVM: x86: Add macro to ensure reserved cr4 bits checks stay in sync")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 53fafdbb8b ("KVM: x86: switch KVMCLOCK base to monotonic raw
clock") changed kvmclock to use tkr_raw instead of tkr_mono. However,
the default kvmclock_offset for the VM was still based on the monotonic
clock and, if the raw clock drifted enough from the monotonic clock,
this could cause a negative system_time to be written to the guest's
struct pvclock. RHEL5 does not like it and (if it boots fast enough to
observe a negative time value) it hangs.
There is another thing to be careful about: getboottime64 returns the
host boot time with tkr_mono frequency, and subtracting the tkr_raw-based
kvmclock value will cause the wallclock to be off if tkr_raw drifts
from tkr_mono. To avoid this, compute the wallclock delta from the
current time instead of being clever and using getboottime64.
Fixes: 53fafdbb8b ("KVM: x86: switch KVMCLOCK base to monotonic raw clock")
Cc: stable@vger.kernel.org
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We will need a copy of tk->offs_boot in the next patch. Store it and
cleanup the struct: instead of storing tk->tkr_xxx.base with the tk->offs_boot
included, store the raw value in struct pvclock_clock and sum it in
do_monotonic_raw and do_realtime. tk->tkr_xxx.xtime_nsec also moves
to struct pvclock_clock.
While at it, fix a (usually harmless) typo in do_monotonic_raw, which
was using gtod->clock.shift instead of gtod->raw_clock.shift.
Fixes: 53fafdbb8b ("KVM: x86: switch KVMCLOCK base to monotonic raw clock")
Cc: stable@vger.kernel.org
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since disabling APICv has to be done for all vcpus on AMD-based
system, adopt the newly introduced kvm_request_apicv_update()
interface, and introduce a new APICV_INHIBIT_REASON_HYPERV.
Also, remove the kvm_vcpu_deactivate_apicv() since no longer used.
Cc: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
AMD SVM AVIC needs to update APIC backing page mapping before changing
APICv mode. Introduce struct kvm_x86_ops.pre_update_apicv_exec_ctrl
function hook to be called prior KVM APICv update request to each vcpu.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Inibit reason bits are used to determine if APICv deactivation is
applicable for a particular hardware virtualization architecture.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Certain runtime conditions require APICv to be temporary deactivated
during runtime. The current implementation only support run-time
deactivation of APICv when Hyper-V SynIC is enabled, which is not
temporary.
In addition, for AMD, when APICv is (de)activated at runtime,
all vcpus in the VM have to operate in the same mode. Thus the
requesting vcpu must notify the others.
So, introduce the following:
* A new KVM_REQ_APICV_UPDATE request bit
* Interfaces to request all vcpus to update APICv status
* A new interface to update APICV-related parameters for each vcpu
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There are several reasons in which a VM needs to deactivate APICv
e.g. disable APICv via parameter during module loading, or when
enable Hyper-V SynIC support. Additional inhibit reasons will be
introduced later on when dynamic APICv is supported,
Introduce KVM APICv inhibit reason bits along with a new variable,
apicv_inhibit_reasons, to help keep track of APICv state for each VM,
Initially, the APICV_INHIBIT_REASON_DISABLE bit is used to indicate
the case where APICv is disabled during KVM module load.
(e.g. insmod kvm_amd avic=0 or insmod kvm_intel enable_apicv=0).
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
[Do not use get_enable_apicv; consider irqchip_split in svm.c. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
PPC: Bugfixes
x86:
* Support for mapping DAX areas with large nested page table entries.
* Cleanups and bugfixes here too. A particularly important one is
a fix for FPU load when the thread has TIF_NEED_FPU_LOAD. There is
also a race condition which could be used in guest userspace to exploit
the guest kernel, for which the embargo expired today.
* Fast path for IPI delivery vmexits, shaving about 200 clock cycles
from IPI latency.
* Protect against "Spectre-v1/L1TF" (bring data in the cache via
speculative out of bound accesses, use L1TF on the sibling hyperthread
to read it), which unfortunately is an even bigger whack-a-mole game
than SpectreV1.
Sean continues his mission to rewrite KVM. In addition to a sizable
number of x86 patches, this time he contributed a pretty large refactoring
of vCPU creation that affects all architectures but should not have any
visible effect.
s390 will come next week together with some more x86 patches.
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Merge tag 'kvm-5.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"This is the first batch of KVM changes.
ARM:
- cleanups and corner case fixes.
PPC:
- Bugfixes
x86:
- Support for mapping DAX areas with large nested page table entries.
- Cleanups and bugfixes here too. A particularly important one is a
fix for FPU load when the thread has TIF_NEED_FPU_LOAD. There is
also a race condition which could be used in guest userspace to
exploit the guest kernel, for which the embargo expired today.
- Fast path for IPI delivery vmexits, shaving about 200 clock cycles
from IPI latency.
- Protect against "Spectre-v1/L1TF" (bring data in the cache via
speculative out of bound accesses, use L1TF on the sibling
hyperthread to read it), which unfortunately is an even bigger
whack-a-mole game than SpectreV1.
Sean continues his mission to rewrite KVM. In addition to a sizable
number of x86 patches, this time he contributed a pretty large
refactoring of vCPU creation that affects all architectures but should
not have any visible effect.
s390 will come next week together with some more x86 patches"
* tag 'kvm-5.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (204 commits)
x86/KVM: Clean up host's steal time structure
x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed
x86/kvm: Cache gfn to pfn translation
x86/kvm: Introduce kvm_(un)map_gfn()
x86/kvm: Be careful not to clear KVM_VCPU_FLUSH_TLB bit
KVM: PPC: Book3S PR: Fix -Werror=return-type build failure
KVM: PPC: Book3S HV: Release lock on page-out failure path
KVM: arm64: Treat emulated TVAL TimerValue as a signed 32-bit integer
KVM: arm64: pmu: Only handle supported event counters
KVM: arm64: pmu: Fix chained SW_INCR counters
KVM: arm64: pmu: Don't mark a counter as chained if the odd one is disabled
KVM: arm64: pmu: Don't increment SW_INCR if PMCR.E is unset
KVM: x86: Use a typedef for fastop functions
KVM: X86: Add 'else' to unify fastop and execute call path
KVM: x86: inline memslot_valid_for_gpte
KVM: x86/mmu: Use huge pages for DAX-backed files
KVM: x86/mmu: Remove lpage_is_disallowed() check from set_spte()
KVM: x86/mmu: Fold max_mapping_level() into kvm_mmu_hugepage_adjust()
KVM: x86/mmu: Zap any compound page when collapsing sptes
KVM: x86/mmu: Remove obsolete gfn restoration in FNAME(fetch)
...
From Boris Ostrovsky:
The KVM hypervisor may provide a guest with ability to defer remote TLB
flush when the remote VCPU is not running. When this feature is used,
the TLB flush will happen only when the remote VPCU is scheduled to run
again. This will avoid unnecessary (and expensive) IPIs.
Under certain circumstances, when a guest initiates such deferred action,
the hypervisor may miss the request. It is also possible that the guest
may mistakenly assume that it has already marked remote VCPU as needing
a flush when in fact that request had already been processed by the
hypervisor. In both cases this will result in an invalid translation
being present in a vCPU, potentially allowing accesses to memory locations
in that guest's address space that should not be accessible.
Note that only intra-guest memory is vulnerable.
The five patches address both of these problems:
1. The first patch makes sure the hypervisor doesn't accidentally clear
a guest's remote flush request
2. The rest of the patches prevent the race between hypervisor
acknowledging a remote flush request and guest issuing a new one.
Conflicts:
arch/x86/kvm/x86.c [move from kvm_arch_vcpu_free to kvm_arch_vcpu_destroy]
Now that we are mapping kvm_steal_time from the guest directly we
don't need keep a copy of it in kvm_vcpu_arch.st. The same is true
for the stime field.
This is part of CVE-2019-3016.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There is a potential race in record_steal_time() between setting
host-local vcpu->arch.st.steal.preempted to zero (i.e. clearing
KVM_VCPU_PREEMPTED) and propagating this value to the guest with
kvm_write_guest_cached(). Between those two events the guest may
still see KVM_VCPU_PREEMPTED in its copy of kvm_steal_time, set
KVM_VCPU_FLUSH_TLB and assume that hypervisor will do the right
thing. Which it won't.
Instad of copying, we should map kvm_steal_time and that will
guarantee atomicity of accesses to @preempted.
This is part of CVE-2019-3016.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
__kvm_map_gfn()'s call to gfn_to_pfn_memslot() is
* relatively expensive
* in certain cases (such as when done from atomic context) cannot be called
Stashing gfn-to-pfn mapping should help with both cases.
This is part of CVE-2019-3016.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_steal_time_set_preempted() may accidentally clear KVM_VCPU_FLUSH_TLB
bit if it is called more than once while VCPU is preempted.
This is part of CVE-2019-3016.
(This bug was also independently discovered by Jim Mattson
<jmattson@google.com>)
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_vector_hashing_enabled() is just called in kvm.ko module.
Signed-off-by: Peng Hao <richard.peng@oppo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
According to section "Checks on Guest Control Registers, Debug Registers, and
and MSRs" in Intel SDM vol 3C, the following checks are performed on vmentry
of nested guests:
If the "load debug controls" VM-entry control is 1, bits 63:32 in the DR7
field must be 0.
In KVM, GUEST_DR7 is set prior to the vmcs02 VM-entry by kvm_set_dr() and the
latter synthesizes a #GP if any bit in the high dword in the former is set.
Hence this field needs to be checked in software.
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The helper x86_set_memory_region() is only used in vmx_set_tss_addr()
and kvm_arch_destroy_vm(). Push the lock upper in both cases. With
that, drop x86_set_memory_region().
This prepares to allow __x86_set_memory_region() to return a HVA
mapped, because the HVA will need to be protected by the lock too even
after __x86_set_memory_region() returns.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reload the current thread's FPU state, which contains the guest's FPU
state, to the CPU registers if necessary during vcpu_enter_guest().
TIF_NEED_FPU_LOAD can be set any time control is transferred out of KVM,
e.g. if I/O is triggered during a KVM call to get_user_pages() or if a
softirq occurs while KVM is scheduled in.
Moving the handling of TIF_NEED_FPU_LOAD from vcpu_enter_guest() to
kvm_arch_vcpu_load(), effectively kvm_sched_in(), papered over a bug
where kvm_put_guest_fpu() failed to account for TIF_NEED_FPU_LOAD. The
easiest way to the kvm_put_guest_fpu() bug was to run with involuntary
preemption enable, thus handling TIF_NEED_FPU_LOAD during kvm_sched_in()
made the bug go away. But, removing the handling in vcpu_enter_guest()
exposed KVM to the rare case of a softirq triggering kernel_fpu_begin()
between vcpu_load() and vcpu_enter_guest().
Now that kvm_{load,put}_guest_fpu() correctly handle TIF_NEED_FPU_LOAD,
revert the commit to both restore the vcpu_enter_guest() behavior and
eliminate the superfluous switch_fpu_return() in kvm_arch_vcpu_load().
Note, leaving the handling in kvm_arch_vcpu_load() isn't wrong per se,
but it is unnecessary, and most critically, makes it extremely difficult
to find bugs such as the kvm_put_guest_fpu() issue due to shrinking the
window where a softirq can corrupt state.
A sample trace triggered by warning if TIF_NEED_FPU_LOAD is set while
vcpu state is loaded:
<IRQ>
gcmaes_crypt_by_sg.constprop.12+0x26e/0x660
? 0xffffffffc024547d
? __qdisc_run+0x83/0x510
? __dev_queue_xmit+0x45e/0x990
? ip_finish_output2+0x1a8/0x570
? fib4_rule_action+0x61/0x70
? fib4_rule_action+0x70/0x70
? fib_rules_lookup+0x13f/0x1c0
? helper_rfc4106_decrypt+0x82/0xa0
? crypto_aead_decrypt+0x40/0x70
? crypto_aead_decrypt+0x40/0x70
? crypto_aead_decrypt+0x40/0x70
? esp_output_tail+0x8f4/0xa5a [esp4]
? skb_ext_add+0xd3/0x170
? xfrm_input+0x7a6/0x12c0
? xfrm4_rcv_encap+0xae/0xd0
? xfrm4_transport_finish+0x200/0x200
? udp_queue_rcv_one_skb+0x1ba/0x460
? udp_unicast_rcv_skb.isra.63+0x72/0x90
? __udp4_lib_rcv+0x51b/0xb00
? ip_protocol_deliver_rcu+0xd2/0x1c0
? ip_local_deliver_finish+0x44/0x50
? ip_local_deliver+0xe0/0xf0
? ip_protocol_deliver_rcu+0x1c0/0x1c0
? ip_rcv+0xbc/0xd0
? ip_rcv_finish_core.isra.19+0x380/0x380
? __netif_receive_skb_one_core+0x7e/0x90
? netif_receive_skb_internal+0x3d/0xb0
? napi_gro_receive+0xed/0x150
? 0xffffffffc0243c77
? net_rx_action+0x149/0x3b0
? __do_softirq+0xe4/0x2f8
? handle_irq_event_percpu+0x6a/0x80
? irq_exit+0xe6/0xf0
? do_IRQ+0x7f/0xd0
? common_interrupt+0xf/0xf
</IRQ>
? irq_entries_start+0x20/0x660
? vmx_get_interrupt_shadow+0x2f0/0x710 [kvm_intel]
? kvm_set_msr_common+0xfc7/0x2380 [kvm]
? recalibrate_cpu_khz+0x10/0x10
? ktime_get+0x3a/0xa0
? kvm_arch_vcpu_ioctl_run+0x107/0x560 [kvm]
? kvm_init+0x6bf/0xd00 [kvm]
? __seccomp_filter+0x7a/0x680
? do_vfs_ioctl+0xa4/0x630
? security_file_ioctl+0x32/0x50
? ksys_ioctl+0x60/0x90
? __x64_sys_ioctl+0x16/0x20
? do_syscall_64+0x5f/0x1a0
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
---[ end trace 9564a1ccad733a90 ]---
This reverts commit e751732486.
Fixes: e751732486 ("KVM: X86: Fix fpu state crash in kvm guest")
Reported-by: Derek Yerger <derek@djy.llc>
Reported-by: kernel@najdan.com
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Thomas Lambertz <mail@thomaslambertz.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Handle TIF_NEED_FPU_LOAD similar to how fpu__copy() handles the flag
when duplicating FPU state to a new task struct. TIF_NEED_FPU_LOAD can
be set any time control is transferred out of KVM, be it voluntarily,
e.g. if I/O is triggered during a KVM call to get_user_pages, or
involuntarily, e.g. if softirq runs after an IRQ occurs. Therefore,
KVM must account for TIF_NEED_FPU_LOAD whenever it is (potentially)
accessing CPU FPU state.
Fixes: 5f409e20b7 ("x86/fpu: Defer FPU state load until return to userspace")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This reverts commit 95145c25a7.
The next few patches will fix the issue so the warning is not
needed anymore; revert it separately to simplify application to
stable kernels.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The exception pending event is cleared by kvm_clear_exception_queue(). We
shouldn't clear it again.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This fixes a Spectre-v1/L1TF vulnerability in __kvm_set_dr() and
kvm_get_dr().
Both kvm_get_dr() and kvm_set_dr() (a wrapper of __kvm_set_dr()) are
exported symbols so KVM should tream them conservatively from a security
perspective.
Fixes: 020df0794f ("KVM: move DR register access handling into generic code")
Signed-off-by: Nick Finco <nifi@google.com>
Signed-off-by: Marios Pomonis <pomonis@google.com>
Reviewed-by: Andrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This fixes a Spectre-v1/L1TF vulnerability in set_msr_mce() and
get_msr_mce().
Both functions contain index computations based on the
(attacker-controlled) MSR number.
Fixes: 890ca9aefa ("KVM: Add MCE support")
Signed-off-by: Nick Finco <nifi@google.com>
Signed-off-by: Marios Pomonis <pomonis@google.com>
Reviewed-by: Andrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove kvm_arch_vcpu_init() and kvm_arch_vcpu_uninit() now that all
arch specific implementations are nops.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Fold init() into create() now that the two are called back-to-back by
common KVM code (kvm_vcpu_init() calls kvm_arch_vcpu_init() as its last
action, and kvm_vm_ioctl_create_vcpu() calls kvm_arch_vcpu_create()
immediately thereafter). This paves the way for removing
kvm_arch_vcpu_init() entirely.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove kvm_arch_vcpu_setup() now that all arch specific implementations
are nops.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Fold setup() into create() now that the two are called back-to-back by
common KVM code. This paves the way for removing kvm_arch_vcpu_setup().
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
