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kvm: svm: Use the hardware provided GPA instead of page walk

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When a guest causes a NPF which requires emulation, KVM sometimes walks
the guest page tables to translate the GVA to a GPA. This is unnecessary
most of the time on AMD hardware since the hardware provides the GPA in
EXITINFO2.

The only exception cases involve string operations involving rep or
operations that use two memory locations. With rep, the GPA will only be
the value of the initial NPF and with dual memory locations we won't know
which memory address was translated into EXITINFO2.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Tom Lendacky
2016-12-14 14:59:23 -05:00
committed by Radim Krčmář
parent 5bd5db385b
commit 0f89b207b0
5 changed files with 57 additions and 14 deletions
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arch/x86/include/asm/kvm_emulate.h
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@@ -441,5 +441,6 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt);
void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt);
bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt);
#endif /* _ASM_X86_KVM_X86_EMULATE_H */