| Message ID | 50E6DF5C.2000103@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@linux.vnet.ibm.com> > --- > 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. 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). > /* > * if emulation was due to access to shadowed page table > * and it failed try to unshadow page and re-enter the > * guest to let CPU execute the instruction. > */ > - if (kvm_mmu_unprotect_page_virt(vcpu, gva)) > + if (kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa))) > return true; > > - gpa = kvm_mmu_gva_to_gpa_system(vcpu, gva, NULL); > - > - if (gpa == UNMAPPED_GVA) > - return true; /* let cpu generate fault */ > - > /* > * Do not retry the unhandleable instruction if it faults on the > * readonly host memory, otherwise it will goto a infinite loop: > @@ -4828,7 +4827,7 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, > if (!vcpu->arch.mmu.direct_map) > gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2, NULL); > > - kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT); > + kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa)); > > return true; > } > -- > 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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@linux.vnet.ibm.com> >> --- >> 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 */ + /* * if emulation was due to access to shadowed page table * and it failed try to unshadow page and re-enter the * guest to let CPU execute the instruction. */ - if (kvm_mmu_unprotect_page_virt(vcpu, gva)) + if (kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa))) return true; - gpa = kvm_mmu_gva_to_gpa_system(vcpu, gva, NULL); - - if (gpa == UNMAPPED_GVA) - return true; /* let cpu generate fault */ - /* * Do not retry the unhandleable instruction if it faults on the * readonly host memory, otherwise it will goto a infinite loop: @@ -4828,7 +4827,7 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, if (!vcpu->arch.mmu.direct_map) gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2, NULL); - kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT); + kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa)); return true; }
Little cleanup for reexecute_instruction, also use gpa_to_gfn in retry_instruction Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> --- arch/x86/kvm/x86.c | 13 ++++++------- 1 files changed, 6 insertions(+), 7 deletions(-)