Commit d855066f authored by Like Xu's avatar Like Xu Committed by Paolo Bonzini
Browse files

KVM: VMX: read/write MSR_IA32_DEBUGCTLMSR from GUEST_IA32_DEBUGCTL 



SVM already has specific handlers of MSR_IA32_DEBUGCTLMSR in the
svm_get/set_msr, so the x86 common part can be safely moved to VMX.
This allows KVM to store the bits it supports in GUEST_IA32_DEBUGCTL.

Add vmx_supported_debugctl() to refactor the throwing logic of #GP.

Signed-off-by: default avatarLike Xu <like.xu@linux.intel.com>
Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
Message-Id: <20210108013704.134985-2-like.xu@linux.intel.com>
[Merge parts of Chenyi Qiang's "KVM: X86: Expose bus lock debug exception
 to guest". - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 563c54c4

arch/x86/kvm/vmx/capabilities.h

+5 −0
Original line number Diff line number Diff line
@@ -384,4 +384,9 @@ static inline u64 vmx_get_perf_capabilities(void) 
	return PMU_CAP_FW_WRITES;

}



static inline u64 vmx_supported_debugctl(void)

{

	return 0;

}



#endif /* __KVM_X86_VMX_CAPS_H */

arch/x86/kvm/vmx/vmx.c

+19 −4
Original line number Diff line number Diff line
@@ -1924,6 +1924,9 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 
		    !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))

			return 1;

		goto find_uret_msr;

	case MSR_IA32_DEBUGCTLMSR:

		msr_info->data = vmcs_read64(GUEST_IA32_DEBUGCTL);

		break;

	default:

	find_uret_msr:

		msr = vmx_find_uret_msr(vmx, msr_info->index);
@@ -1997,14 +2000,26 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 
		}

		vmcs_writel(GUEST_SYSENTER_ESP, data);

		break;

	case MSR_IA32_DEBUGCTLMSR:

	case MSR_IA32_DEBUGCTLMSR: {

		u64 invalid = data & ~vmx_supported_debugctl();

		if (invalid & (DEBUGCTLMSR_BTF|DEBUGCTLMSR_LBR)) {

			if (report_ignored_msrs)

				vcpu_unimpl(vcpu, "%s: BTF|LBR in IA32_DEBUGCTLMSR 0x%llx, nop\n",

					    __func__, data);

			data &= ~(DEBUGCTLMSR_BTF|DEBUGCTLMSR_LBR);

			invalid &= ~(DEBUGCTLMSR_BTF|DEBUGCTLMSR_LBR);

		}



		if (invalid)

			return 1;



		if (is_guest_mode(vcpu) && get_vmcs12(vcpu)->vm_exit_controls &

						VM_EXIT_SAVE_DEBUG_CONTROLS)

			get_vmcs12(vcpu)->guest_ia32_debugctl = data;



		ret = kvm_set_msr_common(vcpu, msr_info);

		break;



		vmcs_write64(GUEST_IA32_DEBUGCTL, data);

		return 0;

	}

	case MSR_IA32_BNDCFGS:

		if (!kvm_mpx_supported() ||

		    (!msr_info->host_initiated &&

arch/x86/kvm/x86.c

+2 −14
Original line number Diff line number Diff line
@@ -117,8 +117,9 @@ EXPORT_SYMBOL_GPL(kvm_x86_ops); 
static bool __read_mostly ignore_msrs = 0;

module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);



static bool __read_mostly report_ignored_msrs = true;

bool __read_mostly report_ignored_msrs = true;

module_param(report_ignored_msrs, bool, S_IRUGO | S_IWUSR);

EXPORT_SYMBOL_GPL(report_ignored_msrs);



unsigned int min_timer_period_us = 200;

module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);
@@ -3073,18 +3074,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 
			return 1;

		}

		break;

	case MSR_IA32_DEBUGCTLMSR:

		if (!data) {

			/* We support the non-activated case already */

			break;

		} else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) {

			/* Values other than LBR and BTF are vendor-specific,

			   thus reserved and should throw a #GP */

			return 1;

		} else if (report_ignored_msrs)

			vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",

				    __func__, data);

		break;

	case 0x200 ... 0x2ff:

		return kvm_mtrr_set_msr(vcpu, msr, data);

	case MSR_IA32_APICBASE:
@@ -3357,7 +3346,6 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 
	switch (msr_info->index) {

	case MSR_IA32_PLATFORM_ID:

	case MSR_IA32_EBL_CR_POWERON:

	case MSR_IA32_DEBUGCTLMSR:

	case MSR_IA32_LASTBRANCHFROMIP:

	case MSR_IA32_LASTBRANCHTOIP:

	case MSR_IA32_LASTINTFROMIP:

arch/x86/kvm/x86.h

+2 −0
Original line number Diff line number Diff line
@@ -296,6 +296,8 @@ extern int pi_inject_timer; 


extern struct static_key kvm_no_apic_vcpu;



extern bool report_ignored_msrs;



static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)

{

	return pvclock_scale_delta(nsec, vcpu->arch.virtual_tsc_mult,