x86: kvm: svm: propagate errors from skip_emulated_instruction()

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On AMD, kvm_x86_ops->skip_emulated_instruction(vcpu) can, in theory,
fail: in !nrips case we call kvm_emulate_instruction(EMULTYPE_SKIP).
Currently, we only do printk(KERN_DEBUG) when this happens and this
is not ideal. Propagate the error up the stack.

On VMX, skip_emulated_instruction() doesn't fail, we have two call
sites calling it explicitly: handle_exception_nmi() and
handle_task_switch(), we can just ignore the result.

On SVM, we also have two explicit call sites:
svm_queue_exception() and it seems we don't need to do anything there as
we check if RIP was advanced or not. In task_switch_interception(),
however, we are better off not proceeding to kvm_task_switch() in case
skip_emulated_instruction() failed.

Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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This commit is contained in:

Vitaly Kuznetsov 2019-08-13 15:53:30 +02:00 • committed by Paolo Bonzini

parent 05402f6454

commit f8ea7c6049

4 changed files with 38 additions and 22 deletions

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2

arch/x86/include/asm/kvm_host.h

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arch/x86/kvm/svm.c

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arch/x86/kvm/vmx/vmx.c

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arch/x86/kvm/x86.c

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