On 01/05/2013 06:21 AM, Marcelo Tosatti wrote: > On Fri, Jan 04, 2013 at 09:55:40PM +0800, Xiao Guangrong wrote: >> Little cleanup for reexecute_instruction, also use gpa_to_gfn in >> retry_instruction >> >> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx> >> --- >> arch/x86/kvm/x86.c | 13 ++++++------- >> 1 files changed, 6 insertions(+), 7 deletions(-) >> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index 1c9c834..ad39018 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -4761,19 +4761,18 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva) >> if (tdp_enabled) >> return false; >> >> + gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL); >> + if (gpa == UNMAPPED_GVA) >> + return true; /* let cpu generate fault */ >> + > > Why change from _system to _read here? Purely cleanup patch should > have no logical changes. Ouch, my mistake, will drop this change. > > BTW, there is not much logic in using reexecute_instruction() at > for x86_decode_insn (checks in reexecute_instruction() assume > write to the cr2, for instance). > Fault propagation for x86_decode_insn seems completly broken > (which is perhaps why reexecute_instruction() there survived). Currently, reexecute_instruction can work only if it is called on page fault path where cr2 is valid. On other paths, cr2 is 0 which is always not be mapped on guest since it is NULL pointer, so reexecute_instruction always retry the instruction. Yes, as you point it out, it is better if the fault address can be got from x86_decode_insn. I will consider it later. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
