KVM: VMX: Use vcpu->arch.regs directly when saving/loading guest state

...now that all other references to struct vcpu_vmx have been removed.

Note that 'vmx' still needs to be passed into the asm blob in _ASM_ARG1
as it is consumed by vmx_update_host_rsp().  And similar to that code,
use _ASM_ARG2 in the assembly code to prepare for moving to proper asm,
while explicitly referencing the exact registers in the clobber list for
clarity in the short term and to avoid additional precompiler games.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

@@ -6382,13 +6382,18 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
 	asm(
 		/* Store host registers */
 		"push %%" _ASM_BP " \n\t"
-		"push %%" _ASM_ARG1 " \n\t"
+
+		/*
+		 * Save @regs, _ASM_ARG2 may be modified by vmx_update_host_rsp() and
+		 * @regs is needed after VM-Exit to save the guest's register values.
+		 */
+		"push %%" _ASM_ARG2 " \n\t"
 
 		/* Adjust RSP to account for the CALL to vmx_vmenter(). */
 		"lea -%c[wordsize](%%" _ASM_SP "), %%" _ASM_ARG2 " \n\t"
 		"call vmx_update_host_rsp \n\t"
 
-		/* Load the vcpu_vmx pointer to RCX. */
+		/* Load RCX with @regs. */
 		"mov (%%" _ASM_SP "), %%" _ASM_CX " \n\t"
 
 		/* Check if vmlaunch or vmresume is needed */
@@ -6421,7 +6426,7 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
 		/* Temporarily save guest's RCX. */
 		"push %%" _ASM_CX " \n\t"
 
-		/* Reload the vcpu_vmx pointer to RCX. */
+		/* Reload RCX with @regs. */
 		"mov %c[wordsize](%%" _ASM_SP "), %%" _ASM_CX " \n\t"
 
 		/* Save all guest registers, including RCX from the stack */
@@ -6486,37 +6491,37 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
 
 	      : ASM_CALL_CONSTRAINT, "=b"(vmx->fail),
 #ifdef CONFIG_X86_64
-		"=D"((int){0})
-	      : "D"(vmx),
+		"=D"((int){0}), "=S"((int){0})
+	      : "D"(vmx), "S"(&vcpu->arch.regs),
 #else
-		"=a"((int){0})
-	      : "a"(vmx),
+		"=a"((int){0}), "=d"((int){0})
+	      : "a"(vmx), "d"(&vcpu->arch.regs),
 #endif
 		"b"(vmx->loaded_vmcs->launched),
-		[rax]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RAX])),
-		[rbx]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RBX])),
-		[rcx]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RCX])),
-		[rdx]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RDX])),
-		[rsi]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RSI])),
-		[rdi]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RDI])),
-		[rbp]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RBP])),
+		[rax]"i"(VCPU_REGS_RAX * sizeof(ulong)),
+		[rbx]"i"(VCPU_REGS_RBX * sizeof(ulong)),
+		[rcx]"i"(VCPU_REGS_RCX * sizeof(ulong)),
+		[rdx]"i"(VCPU_REGS_RDX * sizeof(ulong)),
+		[rsi]"i"(VCPU_REGS_RSI * sizeof(ulong)),
+		[rdi]"i"(VCPU_REGS_RDI * sizeof(ulong)),
+		[rbp]"i"(VCPU_REGS_RBP * sizeof(ulong)),
 #ifdef CONFIG_X86_64
-		[r8]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_R8])),
-		[r9]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_R9])),
-		[r10]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_R10])),
-		[r11]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_R11])),
-		[r12]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_R12])),
-		[r13]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_R13])),
-		[r14]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_R14])),
-		[r15]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_R15])),
+		[r8]"i"(VCPU_REGS_R8 * sizeof(ulong)),
+		[r9]"i"(VCPU_REGS_R9 * sizeof(ulong)),
+		[r10]"i"(VCPU_REGS_R10 * sizeof(ulong)),
+		[r11]"i"(VCPU_REGS_R11 * sizeof(ulong)),
+		[r12]"i"(VCPU_REGS_R12 * sizeof(ulong)),
+		[r13]"i"(VCPU_REGS_R13 * sizeof(ulong)),
+		[r14]"i"(VCPU_REGS_R14 * sizeof(ulong)),
+		[r15]"i"(VCPU_REGS_R15 * sizeof(ulong)),
 #endif
 		[wordsize]"i"(sizeof(ulong))
 	      : "cc", "memory"
 #ifdef CONFIG_X86_64
-		, "rax", "rcx", "rdx", "rsi"
+		, "rax", "rcx", "rdx"
 		, "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
 #else
-		, "ecx", "edx", "edi", "esi"
+		, "ecx", "edi", "esi"
 #endif
 	      );