[PATCH v2 09/12] KVM/X86: Use kvm_vcpu_map in emulator_cmpxchg_emulated

KarimAllah Ahmed
2018-04-15T21:53:15Z

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>
---
v1 -> v2:
- Update to match the new API return codes
---
arch/x86/kvm/x86.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4633674..8d08c11 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5162,9 +5162,9 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
unsigned int bytes,
struct x86_exception *exception)
{
+ struct kvm_host_map map;
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
gpa_t gpa;
- struct page *page;
char *kaddr;
bool exchanged;

@@ -5181,12 +5181,11 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK))
goto emul_write;

- page = kvm_vcpu_gfn_to_page(vcpu, gpa >> PAGE_SHIFT);
- if (is_error_page(page))
+ if (kvm_vcpu_map(vcpu, gpa_to_gfn(gpa), &map))
goto emul_write;

- kaddr = kmap_atomic(page);
- kaddr += offset_in_page(gpa);
+ kaddr = map.hva + offset_in_page(gpa);
+
switch (bytes) {
case 1:
exchanged = CMPXCHG_TYPE(u8, kaddr, old, new);
@@ -5203,8 +5202,8 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
default:
BUG();
}
- kunmap_atomic(kaddr);
- kvm_release_page_dirty(page);
+
+ kvm_vcpu_unmap(&map);

if (!exchanged)
return X86EMUL_CMPXCHG_FAILED;
--
2.7.4