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KVM/X86: Use kvm_vcpu_map in emulator_cmpxchg_emulated 

Use kvm_vcpu_map in emulator_cmpxchg_emulated since using
kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
a "struct page".

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Reviewed-by: Konrad Rzeszutek Wilk <kjonrad.wilk@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
KarimAllah Ahmed 2019-01-31 21:24:39 +01:00 committed by Paolo Bonzini
parent 3278e04925
commit 42e35f8072
1 changed files with 6 additions and 8 deletions
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14
arch/x86/kvm/x86.c
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@ -5557,9 +5557,9 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
unsigned int bytes, unsigned int bytes,
struct x86_exception *exception) struct x86_exception *exception)
{ {
struct kvm_host_map map;
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
gpa_t gpa; gpa_t gpa;
struct page *page;
char *kaddr; char *kaddr;
bool exchanged; bool exchanged;
@ -5576,12 +5576,11 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK)) if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK))
goto emul_write; goto emul_write;
page = kvm_vcpu_gfn_to_page(vcpu, gpa >> PAGE_SHIFT); if (kvm_vcpu_map(vcpu, gpa_to_gfn(gpa), &map))
if (is_error_page(page))
goto emul_write; goto emul_write;
kaddr = kmap_atomic(page); kaddr = map.hva + offset_in_page(gpa);
kaddr += offset_in_page(gpa);
switch (bytes) { switch (bytes) {
case 1: case 1:
exchanged = CMPXCHG_TYPE(u8, kaddr, old, new); exchanged = CMPXCHG_TYPE(u8, kaddr, old, new);
@ -5598,13 +5597,12 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
default: default:
BUG(); BUG();
} }
kunmap_atomic(kaddr);
kvm_release_page_dirty(page); kvm_vcpu_unmap(vcpu, &map, true);
if (!exchanged) if (!exchanged)
return X86EMUL_CMPXCHG_FAILED; return X86EMUL_CMPXCHG_FAILED;
kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT);
kvm_page_track_write(vcpu, gpa, new, bytes); kvm_page_track_write(vcpu, gpa, new, bytes);
return X86EMUL_CONTINUE; return X86EMUL_CONTINUE;