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The original single target IPI fastpath patch forgot to filter the
ICR destination shorthand field. Multicast IPI is not suitable for
this feature since wakeup the multiple sleeping vCPUs will extend
the interrupt disabled time, it especially worse in the over-subscribe
and VM has a little bit more vCPUs scenario. Let's narrow it down to
single target IPI.
Two VMs, each is 76 vCPUs, one running 'ebizzy -M', the other
running cyclictest on all vCPUs, w/ this patch, the avg score
of cyclictest can improve more than 5%. (pv tlb, pv ipi, pv
sched yield are disabled during testing to avoid the disturb).
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1585189202-1708-3-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The WARN_ON is essentially comparing a user-provided value with 0. It is
trivial to trigger it just by passing garbage to KVM_SET_CLOCK. Guests
can break if you do so, but the same applies to every KVM_SET_* ioctl.
So, if it hurts when you do like this, just do not do it.
Reported-by: syzbot+00be5da1d75f1cc95f6b@syzkaller.appspotmail.com
Fixes: 9446e6fce0ab ("KVM: x86: fix WARN_ON check of an unsigned less than zero")
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Naresh Kamboju reported:
Linux version 5.6.0-rc4 (oe-user@oe-host) (gcc version
(GCC)) #1 SMP Sun Mar 1 22:59:08 UTC 2020
kvm: no hardware support
BUG: kernel NULL pointer dereference, address: 000000000000028c
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP NOPTI
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc4 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
04/01/2014
RIP: 0010:kobject_put+0x12/0x1c0
Call Trace:
cpufreq_cpu_put+0x15/0x20
kvm_arch_init+0x1f6/0x2b0
kvm_init+0x31/0x290
? svm_check_processor_compat+0xd/0xd
? svm_check_processor_compat+0xd/0xd
svm_init+0x21/0x23
do_one_initcall+0x61/0x2f0
? rdinit_setup+0x30/0x30
? rcu_read_lock_sched_held+0x4f/0x80
kernel_init_freeable+0x219/0x279
? rest_init+0x250/0x250
kernel_init+0xe/0x110
ret_from_fork+0x27/0x50
Modules linked in:
CR2: 000000000000028c
---[ end trace 239abf40c55c409b ]---
RIP: 0010:kobject_put+0x12/0x1c0
cpufreq policy which is get by cpufreq_cpu_get() can be NULL if it is failure,
this patch takes care of it.
Fixes: aaec7c03de (KVM: x86: avoid useless copy of cpufreq policy)
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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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>
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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>
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Since commit 5f3d45e7f282 ("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: 5f3d45e7f282 ("kvm/x86: add support for MONITOR_TRAP_FLAG")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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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>
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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>
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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>
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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>
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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: f10c729ff965 ("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>
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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: 345599f9a2928 ("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>
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Commit 53fafdbb8b21f ("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: 53fafdbb8b21f ("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>
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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: 53fafdbb8b21f ("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>
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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>
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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>
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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>
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Add trace points when sending request to (de)activate APICv.
Suggested-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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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>
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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>
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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)
...
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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]
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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>
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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>
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__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>
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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>
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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>
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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>
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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>
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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 e751732486eb3f159089a64d1901992b1357e7cc.
Fixes: e751732486eb3 ("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>
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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: 5f409e20b7945 ("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>
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This reverts commit 95145c25a78cc0a9d3cbc75708abde432310c5a1.
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>
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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>
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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: 020df0794f57 ("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>
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in x86.c
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: 890ca9aefa78 ("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>
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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>
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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>
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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>
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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>
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Now that all architectures tightly couple vcpu allocation/free with the
mandatory calls to kvm_{un}init_vcpu(), move the sequences verbatim to
common KVM code.
Move both allocation and initialization in a single patch to eliminate
thrash in arch specific code. The bisection benefits of moving the two
pieces in separate patches is marginal at best, whereas the odds of
introducing a transient arch specific bug are non-zero.
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>
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Add kvm_vcpu_destroy() and wire up all architectures to call the common
function instead of their arch specific implementation. The common
destruction function will be used by future patches to move allocation
and initialization of vCPUs to common KVM code, i.e. to free resources
that are allocated by arch agnostic code.
No functional change intended.
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>
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Move the call to kvm_vcpu_uninit() in kvm_arch_vcpu_destroy() down a few
lines so that it is invoked immediately prior to freeing the vCPU. This
paves the way for moving the uninit and free sequence to common KVM code
without an associated functional change.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a pre-allocation arch hook to handle checks that are currently done
by arch specific code prior to allocating the vCPU object. This paves
the way for moving the allocation to common KVM code.
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>
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Remove the superfluous kvm_arch_vcpu_free() as it is no longer called
from commmon KVM code. Note, kvm_arch_vcpu_destroy() *is* called from
common code, i.e. choosing which function to whack is not completely
arbitrary.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Remove a bogus clearing of apf.msr_val from kvm_arch_vcpu_destroy().
apf.msr_val is only set to a non-zero value by kvm_pv_enable_async_pf(),
which is only reachable by kvm_set_msr_common(), i.e. by writing
MSR_KVM_ASYNC_PF_EN. KVM does not autonomously write said MSR, i.e.
can only be written via KVM_SET_MSRS or KVM_RUN. Since KVM_SET_MSRS and
KVM_RUN are vcpu ioctls, they require a valid vcpu file descriptor.
kvm_arch_vcpu_destroy() is only called if KVM_CREATE_VCPU fails, and KVM
declares KVM_CREATE_VCPU successful once the vcpu fd is installed and
thus visible to userspace. Ergo, apf.msr_val cannot be non-zero when
kvm_arch_vcpu_destroy() is called.
Fixes: 344d9588a9df0 ("KVM: Add PV MSR to enable asynchronous page faults delivery.")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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x86 does not load its MMU until KVM_RUN, which cannot be invoked until
after vCPU creation succeeds. Given that kvm_arch_vcpu_destroy() is
called if and only if vCPU creation fails, it is impossible for the MMU
to be loaded.
Note, the bogus kvm_mmu_unload() call was added during an unrelated
refactoring of vCPU allocation, i.e. was presumably added as an
opportunstic "fix" for a perceived leak.
Fixes: fb3f0f51d92d1 ("KVM: Dynamically allocate vcpus")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Move the kvm_cpu_{un}init() calls to common x86 code as an intermediate
step to removing kvm_cpu_{un}init() altogether.
Note, VMX'x alloc_apic_access_page() and init_rmode_identity_map() are
per-VM allocations and are intentionally kept if vCPU creation fails.
They are freed by kvm_arch_destroy_vm().
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Allocate the pio_data page after creating the MMU and local APIC so that
all direct memory allocations are grouped together. This allows setting
the return value to -ENOMEM prior to starting the allocations instead of
setting it in the fail path for every allocation.
The pio_data page is only consumed when KVM_RUN is invoked, i.e. moving
its allocation has no real functional impact.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The allocation of FPU structs is identical across VMX and SVM, move it
to common x86 code. Somewhat arbitrarily place the allocation so that
it resides directly above the associated initialization via fx_init(),
e.g. instead of retaining its position with respect to the overall vcpu
creation flow. Although the names names kvm_arch_vcpu_create() and
kvm_arch_vcpu_init() might suggest otherwise, x86 does not have a clean
split between 'create' and 'init'. Allocating the struct immediately
prior to the first use arguably improves readability *now*, and will
yield even bigger improvements when kvm_arch_vcpu_init() is removed in
a future patch.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Move allocation of VMX and SVM vcpus to common x86. Although the struct
being allocated is technically a VMX/SVM struct, it can be interpreted
directly as a 'struct kvm_vcpu' because of the pre-existing requirement
that 'struct kvm_vcpu' be located at offset zero of the arch/vendor vcpu
struct.
Remove the message from the build-time assertions regarding placement of
the struct, as compatibility with the arch usercopy region is no longer
the sole dependent on 'struct kvm_vcpu' being at offset zero.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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