KVM/nVMX: Use __vmx_vcpu_run in nested_vmx_check_vmentry_hw

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.

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>
[sean: dropped versioning info from changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20201231002702.2223707-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 459254c4a5f3e81feffc65dc09587cd48e2e9f30..887283b1df4389746e1e894ed31ddb7179491708 100644 (file)
--- 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;
@@ -3057,35 +3058,8 @@ 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 e85aa5faa22d3f348d4db3d0b3c03da664929753..3a6461694fc2502be9d223fed57249cd0d051fe1 100644 (file)
--- 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 3b8ada67e852ef9516b2d36a70d3e9ed69250661..2a6d29c47b31d27cccab73f5d7195b76dfaf4d47 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6658,8 +6658,6 @@ 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 f64c9b57ed001f051aa2248aa464fe4d5fbcce6a..12c53d05a902becd08fa8f07904cba623c32cbd0 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -388,6 +388,7 @@ 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);
 void vmx_set_intercept_for_msr(struct kvm_vcpu *vcpu,