Commit 4bdec12a authored by Suravee Suthikulpanit's avatar Suravee Suthikulpanit Committed by Paolo Bonzini
Browse files

KVM: SVM: Detect X2APIC virtualization (x2AVIC) support 



Add CPUID check for the x2APIC virtualization (x2AVIC) feature.
If available, the SVM driver can support both AVIC and x2AVIC modes
when load the kvm_amd driver with avic=1. The operating mode will be
determined at runtime depending on the guest APIC mode.

Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: default avatarPankaj Gupta <pankaj.gupta@amd.com>
Signed-off-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Message-Id: <20220519102709.24125-4-suravee.suthikulpanit@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent bf348f66

arch/x86/include/asm/svm.h

+3 −0
Original line number Diff line number Diff line
@@ -195,6 +195,9 @@ struct __attribute__ ((__packed__)) vmcb_control_area { 
#define AVIC_ENABLE_SHIFT 31

#define AVIC_ENABLE_MASK (1 << AVIC_ENABLE_SHIFT)



#define X2APIC_MODE_SHIFT 30

#define X2APIC_MODE_MASK (1 << X2APIC_MODE_SHIFT)



#define LBR_CTL_ENABLE_MASK BIT_ULL(0)

#define VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK BIT_ULL(1)

arch/x86/kvm/svm/avic.c

+45 −0
Original line number Diff line number Diff line
@@ -40,6 +40,9 @@ 
#define AVIC_GATAG_TO_VMID(x)		((x >> AVIC_VCPU_ID_BITS) & AVIC_VM_ID_MASK)

#define AVIC_GATAG_TO_VCPUID(x)		(x & AVIC_VCPU_ID_MASK)



static bool force_avic;

module_param_unsafe(force_avic, bool, 0444);



/* Note:

 * This hash table is used to map VM_ID to a struct kvm_svm,

 * when handling AMD IOMMU GALOG notification to schedule in
@@ -50,6 +53,7 @@ static DEFINE_HASHTABLE(svm_vm_data_hash, SVM_VM_DATA_HASH_BITS); 
static u32 next_vm_id = 0;

static bool next_vm_id_wrapped = 0;

static DEFINE_SPINLOCK(svm_vm_data_hash_lock);

enum avic_modes avic_mode;



/*

 * This is a wrapper of struct amd_iommu_ir_data.
@@ -1058,3 +1062,44 @@ void avic_vcpu_unblocking(struct kvm_vcpu *vcpu) 


	avic_vcpu_load(vcpu, vcpu->cpu);

}



/*

 * Note:

 * - The module param avic enable both xAPIC and x2APIC mode.

 * - Hypervisor can support both xAVIC and x2AVIC in the same guest.

 * - The mode can be switched at run-time.

 */

bool avic_hardware_setup(struct kvm_x86_ops *x86_ops)

{

	if (!npt_enabled)

		return false;



	if (boot_cpu_has(X86_FEATURE_AVIC)) {

		avic_mode = AVIC_MODE_X1;

		pr_info("AVIC enabled\n");

	} else if (force_avic) {

		/*

		 * Some older systems does not advertise AVIC support.

		 * See Revision Guide for specific AMD processor for more detail.

		 */

		avic_mode = AVIC_MODE_X1;

		pr_warn("AVIC is not supported in CPUID but force enabled");

		pr_warn("Your system might crash and burn");

	}



	/* AVIC is a prerequisite for x2AVIC. */

	if (boot_cpu_has(X86_FEATURE_X2AVIC)) {

		if (avic_mode == AVIC_MODE_X1) {

			avic_mode = AVIC_MODE_X2;

			pr_info("x2AVIC enabled\n");

		} else {

			pr_warn(FW_BUG "Cannot support x2AVIC due to AVIC is disabled");

			pr_warn(FW_BUG "Try enable AVIC using force_avic option");

		}

	}



	if (avic_mode != AVIC_MODE_NONE)

		amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);



	return !!avic_mode;

}

arch/x86/kvm/svm/svm.c

+2 −13
Original line number Diff line number Diff line
@@ -188,9 +188,6 @@ module_param(tsc_scaling, int, 0444); 
static bool avic;

module_param(avic, bool, 0444);



static bool force_avic;

module_param_unsafe(force_avic, bool, 0444);



bool __read_mostly dump_invalid_vmcb;

module_param(dump_invalid_vmcb, bool, 0644);
@@ -5016,17 +5013,9 @@ static __init int svm_hardware_setup(void) 
			nrips = false;

	}



	enable_apicv = avic = avic && npt_enabled && (boot_cpu_has(X86_FEATURE_AVIC) || force_avic);

	enable_apicv = avic = avic && avic_hardware_setup(&svm_x86_ops);



	if (enable_apicv) {

		if (!boot_cpu_has(X86_FEATURE_AVIC)) {

			pr_warn("AVIC is not supported in CPUID but force enabled");

			pr_warn("Your system might crash and burn");

		} else

			pr_info("AVIC enabled\n");



		amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);

	} else {

	if (!enable_apicv) {

		svm_x86_ops.vcpu_blocking = NULL;

		svm_x86_ops.vcpu_unblocking = NULL;

		svm_x86_ops.vcpu_get_apicv_inhibit_reasons = NULL;

arch/x86/kvm/svm/svm.h

+9 −0
Original line number Diff line number Diff line
@@ -36,6 +36,14 @@ extern bool npt_enabled; 
extern int vgif;

extern bool intercept_smi;



enum avic_modes {

	AVIC_MODE_NONE = 0,

	AVIC_MODE_X1,

	AVIC_MODE_X2,

};



extern enum avic_modes avic_mode;



/*

 * Clean bits in VMCB.

 * VMCB_ALL_CLEAN_MASK might also need to
@@ -607,6 +615,7 @@ extern struct kvm_x86_nested_ops svm_nested_ops; 


/* avic.c */



bool avic_hardware_setup(struct kvm_x86_ops *ops);

int avic_ga_log_notifier(u32 ga_tag);

void avic_vm_destroy(struct kvm *kvm);

int avic_vm_init(struct kvm *kvm);