Commit 9753d688 authored by Aaron Lewis's avatar Aaron Lewis Committed by Paolo Bonzini
Browse files

KVM: VMX: Use wrmsr for switching between guest and host IA32_XSS on Intel 



When the guest can execute the XSAVES/XRSTORS instructions, use wrmsr to
set the hardware IA32_XSS MSR to guest/host values on VM-entry/VM-exit,
rather than the MSR-load areas. By using the same approach as AMD, we
will be able to use a common implementation for both (in the next
patch).

Reviewed-by: default avatarJim Mattson <jmattson@google.com>
Signed-off-by: default avatarAaron Lewis <aaronlewis@google.com>
Change-Id: I9447d104b2615c04e39e4af0c911e1e7309bf464
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 312a1c87

arch/x86/kvm/vmx/vmx.c

+18 −7
Original line number Diff line number Diff line
@@ -2081,13 +2081,6 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 
		if (data != 0)

			return 1;

		vcpu->arch.ia32_xss = data;

		if (vcpu->arch.xsaves_enabled) {

			if (vcpu->arch.ia32_xss != host_xss)

				add_atomic_switch_msr(vmx, MSR_IA32_XSS,

					vcpu->arch.ia32_xss, host_xss, false);

			else

				clear_atomic_switch_msr(vmx, MSR_IA32_XSS);

		}

		break;

	case MSR_IA32_RTIT_CTL:

		if ((pt_mode != PT_MODE_HOST_GUEST) ||
@@ -6473,6 +6466,22 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) 
	}

}



static void vmx_load_guest_xss(struct kvm_vcpu *vcpu)

{

	if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) &&

	    vcpu->arch.xsaves_enabled &&

	    vcpu->arch.ia32_xss != host_xss)

		wrmsrl(MSR_IA32_XSS, vcpu->arch.ia32_xss);

}



static void vmx_load_host_xss(struct kvm_vcpu *vcpu)

{

	if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) &&

	    vcpu->arch.xsaves_enabled &&

	    vcpu->arch.ia32_xss != host_xss)

		wrmsrl(MSR_IA32_XSS, host_xss);

}



bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched);



static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
@@ -6524,6 +6533,7 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) 
		vmx_set_interrupt_shadow(vcpu, 0);



	kvm_load_guest_xcr0(vcpu);

	vmx_load_guest_xss(vcpu);



	if (static_cpu_has(X86_FEATURE_PKU) &&

	    kvm_read_cr4_bits(vcpu, X86_CR4_PKE) &&
@@ -6630,6 +6640,7 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) 
			__write_pkru(vmx->host_pkru);

	}



	vmx_load_host_xss(vcpu);

	kvm_put_guest_xcr0(vcpu);



	vmx->nested.nested_run_pending = 0;