KVM: VMX: Pass "launched" directly to the vCPU-run asm blob

...and remove struct vcpu_vmx's temporary __launched variable.

Eliminating __launched is a bonus, the real motivation is to get to the
point where the only reference to struct vcpu_vmx in the asm code is
to vcpu.arch.regs, which will simplify moving the blob to a proper asm
file.  Note that also means this approach is deliberately different than
what is used in nested_vmx_check_vmentry_hw().

Use BL as it is a callee-save register in both 32-bit and 64-bit ABIs,
i.e. it can't be modified by vmx_update_host_rsp(), to avoid having to
temporarily save/restore the launched flag.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4b8a94fedb769a2746f1c9347ee21252297a13bb..996a13ea86cc7cbb41192cb165e28c5beba410be 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6373,8 +6373,6 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp)
 
 static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
 {
-       vmx->__launched = vmx->loaded_vmcs->launched;
-
        if (static_branch_unlikely(&vmx_l1d_should_flush))
                vmx_l1d_flush(vcpu);
 
@@ -6395,7 +6393,8 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
                "mov (%%" _ASM_SP "), %%" _ASM_CX " \n\t"
 
                /* Check if vmlaunch or vmresume is needed */
-               "cmpb $0, %c[launched](%%" _ASM_CX ") \n\t"
+               "cmpb $0, %%bl \n\t"
+
                /* Load guest registers.  Don't clobber flags. */
                "mov %c[rax](%%" _ASM_CX "), %%" _ASM_AX " \n\t"
                "mov %c[rbx](%%" _ASM_CX "), %%" _ASM_BX " \n\t"
@@ -6471,7 +6470,7 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
                "xor %%edi, %%edi \n\t"
                "xor %%ebp, %%ebp \n\t"
                "pop  %%" _ASM_BP " \n\t"
-             : ASM_CALL_CONSTRAINT,
+             : ASM_CALL_CONSTRAINT, "=b"((int){0}),
 #ifdef CONFIG_X86_64
                "=D"((int){0})
              : "D"(vmx),
@@ -6479,7 +6478,7 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
                "=a"((int){0})
              : "a"(vmx),
 #endif
-               [launched]"i"(offsetof(struct vcpu_vmx, __launched)),
+               "b"(vmx->loaded_vmcs->launched),
                [fail]"i"(offsetof(struct vcpu_vmx, fail)),
                [rax]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RAX])),
                [rbx]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RBX])),
@@ -6501,10 +6500,10 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
                [wordsize]"i"(sizeof(ulong))
              : "cc", "memory"
 #ifdef CONFIG_X86_64
-               , "rax", "rbx", "rcx", "rdx", "rsi"
+               , "rax", "rcx", "rdx", "rsi"
                , "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
 #else
-               , "ebx", "ecx", "edx", "edi", "esi"
+               , "ecx", "edx", "edi", "esi"
 #endif
              );
 

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 8e203b725928a228c1cddd0c36c14ed0621a8c64..6ee6a492efaf6be3f8381e1769e4951157b5275a 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -208,7 +208,7 @@ struct vcpu_vmx {
        struct loaded_vmcs    vmcs01;
        struct loaded_vmcs   *loaded_vmcs;
        struct loaded_vmcs   *loaded_cpu_state;
-       bool                  __launched; /* temporary, used in vmx_vcpu_run */
+
        struct msr_autoload {
                struct vmx_msrs guest;
                struct vmx_msrs host;