On Mon, Nov 07, 2022 at 09:54:32AM -0500, Paolo Bonzini wrote: > @@ -56,6 +59,16 @@ SYM_FUNC_START(__svm_vcpu_run) > /* Move @svm to RDI. */ > mov %_ASM_ARG2, %_ASM_DI > > + /* > + * Use a single vmcb (vmcb01 because it's always valid) for > + * context switching guest state via VMLOAD/VMSAVE, that way > + * the state doesn't need to be copied between vmcb01 and > + * vmcb02 when switching vmcbs for nested virtualization. > + */ > + mov SVM_vmcb01_pa(%_ASM_DI), %_ASM_AX > +1: vmload %_ASM_AX > +2: > + > /* "POP" @vmcb to RAX. */ > pop %_ASM_AX > > @@ -80,16 +93,11 @@ SYM_FUNC_START(__svm_vcpu_run) > /* Enter guest mode */ > sti > > +3: vmrun %_ASM_AX > +4: > + cli > > + /* Pop @svm to RAX while it's the only available register. */ > pop %_ASM_AX > > /* Save all guest registers. */ So Andrew noted that once the vmload has executed any exception taken (say at 3) will crash and burn because %gs is scribbled. Might be good to make a record of this in the code so it can be cleaned up some day. > @@ -159,11 +179,19 @@ SYM_FUNC_START(__svm_vcpu_run) > pop %_ASM_BP > RET > > +10: cmpb $0, kvm_rebooting > jne 2b > ud2 > +30: cmpb $0, kvm_rebooting > + jne 4b > + ud2 > +50: cmpb $0, kvm_rebooting > + jne 6b > + ud2 > > + _ASM_EXTABLE(1b, 10b) > + _ASM_EXTABLE(3b, 30b) > + _ASM_EXTABLE(5b, 50b)
