| Message ID | 20201217184451.201311-1-ubizjak@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM/nVMX: Use __vmx_vcpu_run in nested_vmx_check_vmentry_hw | expand |
On 17/12/20 19:44, Uros Bizjak wrote: > Replace inline assembly in nested_vmx_check_vmentry_hw > with a call to __vmx_vcpu_run. The function is not > performance critical, so (double) GPR save/restore > in __vmx_vcpu_run can be tolerated, as far as performance > effects are concerned. > > v2: Mark vmx_vmenter SYM_FUNC_START_LOCAL. > > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Sean Christopherson <seanjc@google.com> > Reviewed-and-tested-by: Sean Christopherson <seanjc@google.com> > Signed-off-by: Uros Bizjak <ubizjak@gmail.com> > --- > arch/x86/kvm/vmx/nested.c | 32 +++----------------------------- > arch/x86/kvm/vmx/vmenter.S | 2 +- > arch/x86/kvm/vmx/vmx.c | 2 -- > arch/x86/kvm/vmx/vmx.h | 1 + > 4 files changed, 5 insertions(+), 32 deletions(-) > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c > index 89af692deb7e..6ab62bf277c4 100644 > --- a/arch/x86/kvm/vmx/nested.c > +++ b/arch/x86/kvm/vmx/nested.c > @@ -12,6 +12,7 @@ > #include "nested.h" > #include "pmu.h" > #include "trace.h" > +#include "vmx.h" > #include "x86.h" > > static bool __read_mostly enable_shadow_vmcs = 1; > @@ -3056,35 +3057,8 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu) > vmx->loaded_vmcs->host_state.cr4 = cr4; > } > > - asm( > - "sub $%c[wordsize], %%" _ASM_SP "\n\t" /* temporarily adjust RSP for CALL */ > - "cmp %%" _ASM_SP ", %c[host_state_rsp](%[loaded_vmcs]) \n\t" > - "je 1f \n\t" > - __ex("vmwrite %%" _ASM_SP ", %[HOST_RSP]") "\n\t" > - "mov %%" _ASM_SP ", %c[host_state_rsp](%[loaded_vmcs]) \n\t" > - "1: \n\t" > - "add $%c[wordsize], %%" _ASM_SP "\n\t" /* un-adjust RSP */ > - > - /* Check if vmlaunch or vmresume is needed */ > - "cmpb $0, %c[launched](%[loaded_vmcs])\n\t" > - > - /* > - * VMLAUNCH and VMRESUME clear RFLAGS.{CF,ZF} on VM-Exit, set > - * RFLAGS.CF on VM-Fail Invalid and set RFLAGS.ZF on VM-Fail > - * Valid. vmx_vmenter() directly "returns" RFLAGS, and so the > - * results of VM-Enter is captured via CC_{SET,OUT} to vm_fail. > - */ > - "call vmx_vmenter\n\t" > - > - CC_SET(be) > - : ASM_CALL_CONSTRAINT, CC_OUT(be) (vm_fail) > - : [HOST_RSP]"r"((unsigned long)HOST_RSP), > - [loaded_vmcs]"r"(vmx->loaded_vmcs), > - [launched]"i"(offsetof(struct loaded_vmcs, launched)), > - [host_state_rsp]"i"(offsetof(struct loaded_vmcs, host_state.rsp)), > - [wordsize]"i"(sizeof(ulong)) > - : "memory" > - ); > + vm_fail = __vmx_vcpu_run(vmx, (unsigned long *)&vcpu->arch.regs, > + vmx->loaded_vmcs->launched); > > if (vmx->msr_autoload.host.nr) > vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr); > diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S > index 90ad7a6246e3..14abe1e37359 100644 > --- a/arch/x86/kvm/vmx/vmenter.S > +++ b/arch/x86/kvm/vmx/vmenter.S > @@ -44,7 +44,7 @@ > * they VM-Fail, whereas a successful VM-Enter + VM-Exit will jump > * to vmx_vmexit. > */ > -SYM_FUNC_START(vmx_vmenter) > +SYM_FUNC_START_LOCAL(vmx_vmenter) > /* EFLAGS.ZF is set if VMCS.LAUNCHED == 0 */ > je 2f > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 47b8357b9751..72b496c54bc9 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6593,8 +6593,6 @@ static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) > } > } > > -bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched); > - > static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, > struct vcpu_vmx *vmx) > { > diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h > index f6f66e5c6510..32db3b033e9b 100644 > --- a/arch/x86/kvm/vmx/vmx.h > +++ b/arch/x86/kvm/vmx/vmx.h > @@ -339,6 +339,7 @@ void vmx_set_virtual_apic_mode(struct kvm_vcpu *vcpu); > struct vmx_uret_msr *vmx_find_uret_msr(struct vcpu_vmx *vmx, u32 msr); > void pt_update_intercept_for_msr(struct kvm_vcpu *vcpu); > void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp); > +bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched); > int vmx_find_loadstore_msr_slot(struct vmx_msrs *m, u32 msr); > void vmx_ept_load_pdptrs(struct kvm_vcpu *vcpu); > > Queued, thanks. Paolo
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 89af692deb7e..6ab62bf277c4 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -12,6 +12,7 @@ #include "nested.h" #include "pmu.h" #include "trace.h" +#include "vmx.h" #include "x86.h" static bool __read_mostly enable_shadow_vmcs = 1; @@ -3056,35 +3057,8 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu) vmx->loaded_vmcs->host_state.cr4 = cr4; } - asm( - "sub $%c[wordsize], %%" _ASM_SP "\n\t" /* temporarily adjust RSP for CALL */ - "cmp %%" _ASM_SP ", %c[host_state_rsp](%[loaded_vmcs]) \n\t" - "je 1f \n\t" - __ex("vmwrite %%" _ASM_SP ", %[HOST_RSP]") "\n\t" - "mov %%" _ASM_SP ", %c[host_state_rsp](%[loaded_vmcs]) \n\t" - "1: \n\t" - "add $%c[wordsize], %%" _ASM_SP "\n\t" /* un-adjust RSP */ - - /* Check if vmlaunch or vmresume is needed */ - "cmpb $0, %c[launched](%[loaded_vmcs])\n\t" - - /* - * VMLAUNCH and VMRESUME clear RFLAGS.{CF,ZF} on VM-Exit, set - * RFLAGS.CF on VM-Fail Invalid and set RFLAGS.ZF on VM-Fail - * Valid. vmx_vmenter() directly "returns" RFLAGS, and so the - * results of VM-Enter is captured via CC_{SET,OUT} to vm_fail. - */ - "call vmx_vmenter\n\t" - - CC_SET(be) - : ASM_CALL_CONSTRAINT, CC_OUT(be) (vm_fail) - : [HOST_RSP]"r"((unsigned long)HOST_RSP), - [loaded_vmcs]"r"(vmx->loaded_vmcs), - [launched]"i"(offsetof(struct loaded_vmcs, launched)), - [host_state_rsp]"i"(offsetof(struct loaded_vmcs, host_state.rsp)), - [wordsize]"i"(sizeof(ulong)) - : "memory" - ); + vm_fail = __vmx_vcpu_run(vmx, (unsigned long *)&vcpu->arch.regs, + vmx->loaded_vmcs->launched); if (vmx->msr_autoload.host.nr) vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr); diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index 90ad7a6246e3..14abe1e37359 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -44,7 +44,7 @@ * they VM-Fail, whereas a successful VM-Enter + VM-Exit will jump * to vmx_vmexit. */ -SYM_FUNC_START(vmx_vmenter) +SYM_FUNC_START_LOCAL(vmx_vmenter) /* EFLAGS.ZF is set if VMCS.LAUNCHED == 0 */ je 2f diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 47b8357b9751..72b496c54bc9 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6593,8 +6593,6 @@ static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) } } -bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched); - static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx) { diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index f6f66e5c6510..32db3b033e9b 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -339,6 +339,7 @@ void vmx_set_virtual_apic_mode(struct kvm_vcpu *vcpu); struct vmx_uret_msr *vmx_find_uret_msr(struct vcpu_vmx *vmx, u32 msr); void pt_update_intercept_for_msr(struct kvm_vcpu *vcpu); void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp); +bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched); int vmx_find_loadstore_msr_slot(struct vmx_msrs *m, u32 msr); void vmx_ept_load_pdptrs(struct kvm_vcpu *vcpu);
Replace inline assembly in nested_vmx_check_vmentry_hw with a call to __vmx_vcpu_run. The function is not performance critical, so (double) GPR save/restore in __vmx_vcpu_run can be tolerated, as far as performance effects are concerned. v2: Mark vmx_vmenter SYM_FUNC_START_LOCAL. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Reviewed-and-tested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> --- arch/x86/kvm/vmx/nested.c | 32 +++----------------------------- arch/x86/kvm/vmx/vmenter.S | 2 +- arch/x86/kvm/vmx/vmx.c | 2 -- arch/x86/kvm/vmx/vmx.h | 1 + 4 files changed, 5 insertions(+), 32 deletions(-)