mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-28 13:22:57 +00:00
Code Issues Releases Wiki Activity

KVM: x86/mmu: Block all page faults during kvm_zap_gfn_range()

Browse source 
commit 6d3085e4d8 upstream.

When zapping a GFN range, pass 0 => ALL_ONES for the to-be-invalidated
range to effectively block all page faults while the zap is in-progress.
The invalidation helpers take a host virtual address, whereas zapping a
GFN obviously provides a guest physical address and with the wrong unit
of measurement (frame vs. byte).

Alternatively, KVM could walk all memslots to get the associated HVAs,
but thanks to SMM, that would require multiple lookups.  And practically
speaking, kvm_zap_gfn_range() usage is quite rare and not a hot path,
e.g. MTRR and CR0.CD are almost guaranteed to be done only on vCPU0
during boot, and APICv inhibits are similarly infrequent operations.

Fixes: edb298c663 ("KVM: x86/mmu: bump mmu notifier count in kvm_zap_gfn_range")
Reported-by: Chao Peng <chao.p.peng@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221111001841.2412598-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sean Christopherson 2022-11-11 00:18:41 +00:00 committed by Greg Kroah-Hartman
parent b064431630
commit ee2fa56f07
1 changed files with 2 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
arch/x86/kvm/mmu/mmu.c
View file

@ -6044,7 +6044,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
write_lock(&kvm->mmu_lock);
kvm_mmu_invalidate_begin(kvm, gfn_start, gfn_end);
kvm_mmu_invalidate_begin(kvm, 0, -1ul);
flush = kvm_rmap_zap_gfn_range(kvm, gfn_start, gfn_end);
@ -6058,7 +6058,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
kvm_flush_remote_tlbs_with_address(kvm, gfn_start,
gfn_end - gfn_start);
kvm_mmu_invalidate_end(kvm, gfn_start, gfn_end);
kvm_mmu_invalidate_end(kvm, 0, -1ul);
write_unlock(&kvm->mmu_lock);
}