Fold max_mapping_level() into kvm_mmu_hugepage_adjust() now that HugeTLB
mappings are handled in kvm_mmu_hugepage_adjust(), i.e. there isn't a
need to pre-calculate the max mapping level.  Co-locating all hugepage
checks eliminates a memslot lookup, at the cost of performing the
__mmu_gfn_lpage_is_disallowed() checks while holding mmu_lock.

The latency of lpage_is_disallowed() is likely negligible relative to
the rest of the code run while holding mmu_lock, and can be offset to
some extent by eliminating the mmu_gfn_lpage_is_disallowed() check in
set_spte() in a future patch.  Eliminating the check in set_spte() is
made possible by performing the initial lpage_is_disallowed() checks
while holding mmu_lock.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Zap any compound page, e.g. THP or HugeTLB pages, when zapping sptes
that can potentially be converted to huge sptes after disabling dirty
logging on the associated memslot.  Note, this approach could result in
false positives, e.g. if a random compound page is mapped into the
guest, but mapping non-huge compound pages into the guest is far from
the norm, and toggling dirty logging is not a frequent operation.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Remove logic to retrieve the original gfn now that HugeTLB mappings are
are identified in FNAME(fetch), i.e. FNAME(page_fault) no longer adjusts
the level or gfn.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Remove KVM's HugeTLB specific logic and instead rely on walking the host
page tables (already done for THP) to identify HugeTLB mappings.
Eliminating the HugeTLB-only logic avoids taking mmap_sem and calling
find_vma() for all hugepage compatible page faults, and simplifies KVM's
page fault code by consolidating all hugepage adjustments into a common
helper.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Remove fast_page_fault()'s optimization to stop the shadow walk if the
iterator level drops below the intended map level.  The intended map
level is only acccurate for HugeTLB mappings (THP mappings are detected
after fast_page_fault()), i.e. it's not required for correctness, and
a future patch will also move HugeTLB mapping detection to after
fast_page_fault().
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Explicitly walk the host page tables to identify THP mappings instead
of relying solely on the metadata in struct page.  This sets the stage
for using a common method of identifying huge mappings regardless of the
underlying implementation (HugeTLB vs THB vs DAX), and hopefully avoids
the pitfalls of relying on metadata to identify THP mappings, e.g. see
commit 169226f7 ("mm: thp: handle page cache THP correctly in
PageTransCompoundMap") and the need for KVM to explicitly check for a
THP compound page.  KVM will also naturally work with 1gb THP pages, if
they are ever supported.

Walking the tables for THP mappings is likely marginally slower than
querying metadata, but a future patch will reuse the walk to identify
HugeTLB mappings, at which point eliminating the existing VMA lookup for
HugeTLB will make this a net positive.

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Barret Rhoden <brho@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Refactor transparent_hugepage_adjust() in preparation for walking the
host page tables to identify hugepage mappings, initially for THP pages,
and eventualy for HugeTLB and DAX-backed pages as well.  The latter
cases support 1gb pages, i.e. the adjustment logic needs access to the
max allowed level.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Add a helper, lookup_address_in_mm(), to traverse the page tables of a
given mm struct.  KVM will use the helper to retrieve the host mapping
level, e.g. 4k vs. 2mb vs. 1gb, of a compound (or DAX-backed) page
without having to resort to implementation specific metadata.  E.g. KVM
currently uses different logic for HugeTLB vs. THP, and would add a
third variant for DAX-backed files.

Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Avoid the "writable" check in __gfn_to_hva_many(), which will always fail
on read-only memslots due to gfn_to_hva() assuming writes.  Functionally,
this allows x86 to create large mappings for read-only memslots that
are backed by HugeTLB mappings.

Note, the changelog for commit 05da4558 ("KVM: MMU: large page
support") states "If the largepage contains write-protected pages, a
large pte is not used.", but "write-protected" refers to pages that are
temporarily read-only, e.g. read-only memslots didn't even exist at the
time.

Fixes: 4d8b81ab ("KVM: introduce readonly memslot")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Redone using kvm_vcpu_gfn_to_memslot_prot. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Use kvm_vcpu_gfn_to_hva() when retrieving the host page size so that the
correct set of memslots is used when handling x86 page faults in SMM.

Fixes: 54bf36aa ("KVM: x86: use vcpu-specific functions to read/write/translate GFNs")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Add a helper, is_transparent_hugepage(), to explicitly check whether a
compound page is a THP and use it when populating KVM's secondary MMU.
The explicit check fixes a bug where a remapped compound page, e.g. for
an XDP Rx socket, is mapped into a KVM guest and is mistaken for a THP,
which results in KVM incorrectly creating a huge page in its secondary
MMU.

Fixes: 936a5fe6 ("thp: kvm mmu transparent hugepage support")
Reported-by: syzbot+c9d1fb51ac9d0d10c39d@syzkaller.appspotmail.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Limit KVM's mapping level for HugeTLB based on its calculated max_level.
The max_level check prior to invoking host_mapping_level() only filters
out the case where KVM cannot create a 2mb mapping, it doesn't handle
the scenario where KVM can create a 2mb but not 1gb mapping, and the
host is using a 1gb HugeTLB mapping.

Fixes: 2f57b705 ("KVM: x86/mmu: Persist gfn_lpage_is_disallowed() to max_level")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Check the result of __kvm_gfn_to_hva_cache_init() and return immediately
instead of relying on the kvm_is_error_hva() check to detect errors so
that it's abundantly clear KVM intends to immediately bail on an error.

Note, the hva check is still mandatory to handle errors on subqeuesnt
calls with the same generation.  Similarly, always return -EFAULT on
error so that multiple (bad) calls for a given generation will get the
same result, e.g. on an illegal gfn wrap, propagating the return from
__kvm_gfn_to_hva_cache_init() would cause the initial call to return
-EINVAL and subsequent calls to return -EFAULT.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Barret reported a (technically benign) bug where nr_pages_avail can be
accessed without being initialized if gfn_to_hva_many() fails.

  virt/kvm/kvm_main.c:2193:13: warning: 'nr_pages_avail' may be
  used uninitialized in this function [-Wmaybe-uninitialized]

Rather than simply squashing the warning by initializing nr_pages_avail,
fix the underlying issues by reworking __kvm_gfn_to_hva_cache_init() to
return immediately instead of continuing on.  Now that all callers check
the result and/or bail immediately on a bad hva, there's no need to
explicitly nullify the memslot on error.
Reported-by: Barret Rhoden <brho@google.com>
Fixes: f1b9dd5e ("kvm: Disallow wraparound in kvm_gfn_to_hva_cache_init")
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When reading/writing using the guest/host cache, check for a bad hva
before checking for a NULL memslot, which triggers the slow path for
handing cross-page accesses.  Because the memslot is nullified on error
by __kvm_gfn_to_hva_cache_init(), if the bad hva is encountered after
crossing into a new page, then the kvm_{read,write}_guest() slow path
could potentially write/access the first chunk prior to detecting the
bad hva.

Arguably, performing a partial access is semantically correct from an
architectural perspective, but that behavior is certainly not intended.
In the original implementation, memslot was not explicitly nullified
and therefore the partial access behavior varied based on whether the
memslot itself was null, or if the hva was simply bad.  The current
behavior was introduced as a seemingly unintentional side effect in
commit f1b9dd5e ("kvm: Disallow wraparound in
kvm_gfn_to_hva_cache_init"), which justified the change with "since some
callers don't check the return code from this function, it sit seems
prudent to clear ghc->memslot in the event of an error".

Regardless of intent, the partial access is dependent on _not_ checking
the result of the cache initialization, which is arguably a bug in its
own right, at best simply weird.

Fixes: 8f964525 ("KVM: Allow cross page reads and writes from cached translations.")
Cc: Jim Mattson <jmattson@google.com>
Cc: Andrew Honig <ahonig@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
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>

vmx_set_segment() clears segment cache unconditionally, so we should not
clear it again by calling vmx_segment_cache_clear().
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

These two conditions are in conflict, adding 'else' to reduce checking.
Signed-off-by: Haiwei Li <lihaiwei@tencent.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.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>

After commit 61bd0f66 ("KVM: PPC: Book3S HV: Fix guest time accounting
with VIRT_CPU_ACCOUNTING_GEN"), no one use this function anymore, So better
to remove it.
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

For ring-based dirty log tracking, it will be more efficient to account
writes during schedule-out or schedule-in to the currently running VCPU.
We would like to do it even if the write doesn't use the current VCPU's
address space, as is the case for cached writes (see commit 4e335d9e,
"Revert "KVM: Support vCPU-based gfn->hva cache"", 2017-05-02).

Therefore, add a mechanism to track the currently-loaded kvm_vcpu struct.
There is already something similar in KVM/ARM; one important difference
is that kvm_arch_vcpu_{load,put} have two callers in virt/kvm/kvm_main.c:
we have to update both the architecture-independent vcpu_{load,put} and
the preempt notifiers.

Another change made in the process is to allow using kvm_get_running_vcpu()
in preemptible code.  This is allowed because preempt notifiers ensure
that the value does not change even after the VCPU thread is migrated.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.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>

We've already got the slots_lock, so we should be safe.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

It's already going to reach 2400 Bytes (which is over half of page
size on 4K page archs), so maybe it's good to have this build-time
check in case it overflows when adding new fields.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Remove kvm_read_guest_atomic() because it's not used anywhere.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

In nested_enable_evmcs() evmcs_already_enabled check doesn't really do
anything: controls are already sanitized and we return '0' regardless.
Just drop the check.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Remove the CONFIG_X86_64 condition from the low level non-canonical
helpers to effectively enable non-canonical checks on 32-bit KVM.
Non-canonical checks are performed by hardware if the CPU *supports*
64-bit mode, whether or not the CPU is actually in 64-bit mode is
irrelevant.

For the most part, skipping non-canonical checks on 32-bit KVM is ok-ish
because 32-bit KVM always (hopefully) drops bits 63:32 of whatever value
it's checking before propagating it to hardware, and architecturally,
the expected behavior for the guest is a bit of a grey area since the
vCPU itself doesn't support 64-bit mode.  I.e. a 32-bit KVM guest can
observe the missed checks in several paths, e.g. INVVPID and VM-Enter,
but it's debatable whether or not the missed checks constitute a bug
because technically the vCPU doesn't support 64-bit mode.

The primary motivation for enabling the non-canonical checks is defense
in depth.  As mentioned above, a guest can trigger a missed check via
INVVPID or VM-Enter.  INVVPID is straightforward as it takes a 64-bit
virtual address as part of its 128-bit INVVPID descriptor and fails if
the address is non-canonical, even if INVVPID is executed in 32-bit PM.
Nested VM-Enter is a bit more convoluted as it requires the guest to
write natural width VMCS fields via memory accesses and then VMPTRLD the
VMCS, but it's still possible.  In both cases, KVM is saved from a true
bug only because its flows that propagate values to hardware (correctly)
take "unsigned long" parameters and so drop bits 63:32 of the bad value.

Explicitly performing the non-canonical checks makes it less likely that
a bad value will be propagated to hardware, e.g. in the INVVPID case,
if __invvpid() didn't implicitly drop bits 63:32 then KVM would BUG() on
the resulting unexpected INVVPID failure due to hardware rejecting the
non-canonical address.

The only downside to enabling the non-canonical checks is that it adds a
relatively small amount of overhead, but the affected flows are not hot
paths, i.e. the overhead is negligible.

Note, KVM technically could gate the non-canonical checks on 32-bit KVM
with static_cpu_has(X86_FEATURE_LM), but on bare metal that's an even
bigger waste of code for everyone except the 0.00000000000001% of the
population running on Yonah, and nested 32-bit on 64-bit already fudges
things with respect to 64-bit CPU behavior.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Also do so in nested_vmx_check_host_state as reported by Krish. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Writes to MSR_CORE_PERF_GLOBAL_CONTROL should never fail if the VM-exit
and VM-entry controls are exposed to L1. Promote the checks to perform a
full WARN if kvm_set_msr() fails and remove the now unused macro
SET_MSR_OR_WARN().
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Remove an unused struct x86_emulate_ctxt * param from low level helpers
used to access guest FPU state.  The unused param was left behind by
commit 6ab0b9fe ("x86,kvm: remove KVM emulator get_fpu / put_fpu").

No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.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 e7517324.

Fixes: e7517324 ("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>

Lock the FPU regs and reload the current thread's FPU state, which holds
the guest's FPU state, to the CPU registers if necessary prior to
accessing guest FPU state as part of emulation.  kernel_fpu_begin() can
be called from softirq context, therefore KVM must ensure softirqs are
disabled (locking the FPU regs disables softirqs) when touching CPU FPU
state.

Note, for all intents and purposes this reverts commit 6ab0b9fe
("x86,kvm: remove KVM emulator get_fpu / put_fpu"), but at the time it
was applied, removing get/put_fpu() was correct.  The re-introduction
of {get,put}_fpu() is necessitated by the deferring of FPU state load.

Fixes: 5f409e20 ("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>

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: 5f409e20 ("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 95145c25.
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>

Short-circuit kvm_apic_accept_pic_intr() when pic intr is accepted, there
is no need to proceed further. Also remove unnecessary var r.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
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 Spectre-v1/L1TF vulnerabilities in intel_find_fixed_event()
and intel_rdpmc_ecx_to_pmc().
kvm_rdpmc() (ancestor of intel_find_fixed_event()) and
reprogram_fixed_counter() (ancestor of intel_rdpmc_ecx_to_pmc()) are
exported symbols so KVM should treat them conservatively from a security
perspective.

Fixes: 25462f7f ("KVM: x86/vPMU: Define kvm_pmu_ops to support vPMU function dispatch")
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 __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: 020df079 ("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 vmx_handle_exit().
While exit_reason is set by the hardware and therefore should not be
attacker-influenced, an unknown exit_reason could potentially be used to
perform such an attack.

Fixes: 55d2375e ("KVM: nVMX: Move nested code to dedicated files")
Signed-off-by: Marios Pomonis <pomonis@google.com>
Signed-off-by: Nick Finco <nifi@google.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Andrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

This fixes Spectre-v1/L1TF vulnerabilities in
vmx_read_guest_seg_selector(), vmx_read_guest_seg_base(),
vmx_read_guest_seg_limit() and vmx_read_guest_seg_ar().  When
invoked from emulation, these functions contain index computations
based on the (attacker-influenced) segment value.  Using constants
prevents the attack.

Cc: stable@vger.kernel.org
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: 890ca9ae ("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>