Paolo Bonzini <pbonzini@xxxxxxxxxx> writes:
> The hflags field will contain information about system management mode
> and will be useful for the emulator. Pass the entire field rather than
> just the guest-mode information.
With respect to maintaining maximum isolation between vcpu internals and
the emulator, why not just "bool smm_mode" ?
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> arch/x86/include/asm/kvm_emulate.h | 5 ++++-
> arch/x86/kvm/emulate.c | 6 +++---
> arch/x86/kvm/x86.c | 4 +++-
> 3 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
> index 57a9d94fe160..7410879a41f7 100644
> --- a/arch/x86/include/asm/kvm_emulate.h
> +++ b/arch/x86/include/asm/kvm_emulate.h
> @@ -262,6 +262,9 @@ enum x86emul_mode {
> X86EMUL_MODE_PROT64, /* 64-bit (long) mode. */
> };
>
> +/* These match some of the HF_* flags defined in kvm_host.h */
> +#define X86EMUL_GUEST_MASK (1 << 5) /* VCPU is in guest-mode */
> +
> struct x86_emulate_ctxt {
> const struct x86_emulate_ops *ops;
>
> @@ -273,8 +276,8 @@ struct x86_emulate_ctxt {
>
> /* interruptibility state, as a result of execution of STI or MOV SS */
> int interruptibility;
> + int emul_flags;
>
> - bool guest_mode; /* guest running a nested guest */
> bool perm_ok; /* do not check permissions if true */
> bool ud; /* inject an #UD if host doesn't support insn */
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 630bcb0d7a04..cdb612b50910 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -4871,7 +4871,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
> fetch_possible_mmx_operand(ctxt, &ctxt->dst);
> }
>
> - if (unlikely(ctxt->guest_mode) && (ctxt->d & Intercept)) {
> + if (unlikely(ctxt->emul_flags & X86EMUL_GUEST_MASK) && ctxt->intercept) {
> rc = emulator_check_intercept(ctxt, ctxt->intercept,
> X86_ICPT_PRE_EXCEPT);
> if (rc != X86EMUL_CONTINUE)
> @@ -4900,7 +4900,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
> goto done;
> }
>
> - if (unlikely(ctxt->guest_mode) && (ctxt->d & Intercept)) {
> + if (unlikely(ctxt->emul_flags & X86EMUL_GUEST_MASK) && (ctxt->d & Intercept)) {
> rc = emulator_check_intercept(ctxt, ctxt->intercept,
> X86_ICPT_POST_EXCEPT);
> if (rc != X86EMUL_CONTINUE)
> @@ -4953,7 +4953,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
>
> special_insn:
>
> - if (unlikely(ctxt->guest_mode) && (ctxt->d & Intercept)) {
> + if (unlikely(ctxt->emul_flags & X86EMUL_GUEST_MASK) && (ctxt->d & Intercept)) {
> rc = emulator_check_intercept(ctxt, ctxt->intercept,
> X86_ICPT_POST_MEMACCESS);
> if (rc != X86EMUL_CONTINUE)
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 856598afa6b4..6009e6a0e406 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -5132,7 +5132,8 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
> (cs_l && is_long_mode(vcpu)) ? X86EMUL_MODE_PROT64 :
> cs_db ? X86EMUL_MODE_PROT32 :
> X86EMUL_MODE_PROT16;
> - ctxt->guest_mode = is_guest_mode(vcpu);
> + BUILD_BUG_ON(HF_GUEST_MASK != X86EMUL_GUEST_MASK);
> + ctxt->emul_flags = vcpu->arch.hflags;
>
> init_decode_cache(ctxt);
> vcpu->arch.emulate_regs_need_sync_from_vcpu = false;
> @@ -5500,6 +5501,7 @@ restart:
> unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);
> toggle_interruptibility(vcpu, ctxt->interruptibility);
> vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
> + vcpu->arch.hflags = ctxt->emul_flags;
> kvm_rip_write(vcpu, ctxt->eip);
> if (r == EMULATE_DONE)
> kvm_vcpu_check_singlestep(vcpu, rflags, &r);
--
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