Commit 5db1bef9 authored by Fuad Tabba's avatar Fuad Tabba Committed by Marc Zyngier
Browse files

KVM: arm64: Track SVE state in the hypervisor vcpu structure 



When dealing with a guest with SVE enabled, make sure the host SVE
state is pinned at EL2 S1, and that the hypervisor vCPU state is
correctly initialised (and then unpinned on teardown).

Co-authored-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarFuad Tabba <tabba@google.com>
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416152648.2982950-2-qperret@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent b4432656

arch/arm64/include/asm/kvm_host.h

+7 −5
Original line number Diff line number Diff line
@@ -971,20 +971,22 @@ struct kvm_vcpu_arch { 
#define vcpu_sve_zcr_elx(vcpu)						\

	(unlikely(is_hyp_ctxt(vcpu)) ? ZCR_EL2 : ZCR_EL1)



#define vcpu_sve_state_size(vcpu) ({					\

#define sve_state_size_from_vl(sve_max_vl) ({				\

	size_t __size_ret;						\

	unsigned int __vcpu_vq;						\

	unsigned int __vq;						\

									\

	if (WARN_ON(!sve_vl_valid((vcpu)->arch.sve_max_vl))) {		\

	if (WARN_ON(!sve_vl_valid(sve_max_vl))) {			\

		__size_ret = 0;						\

	} else {							\

		__vcpu_vq = vcpu_sve_max_vq(vcpu);			\

		__size_ret = SVE_SIG_REGS_SIZE(__vcpu_vq);		\

		__vq = sve_vq_from_vl(sve_max_vl);			\

		__size_ret = SVE_SIG_REGS_SIZE(__vq);			\

	}								\

									\

	__size_ret;							\

})



#define vcpu_sve_state_size(vcpu) sve_state_size_from_vl((vcpu)->arch.sve_max_vl)



#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \

				 KVM_GUESTDBG_USE_SW_BP | \

				 KVM_GUESTDBG_USE_HW | \

arch/arm64/kvm/hyp/nvhe/hyp-main.c

+0 −4
Original line number Diff line number Diff line
@@ -123,10 +123,6 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu) 


	hyp_vcpu->vcpu.arch.ctxt	= host_vcpu->arch.ctxt;



	hyp_vcpu->vcpu.arch.sve_state	= kern_hyp_va(host_vcpu->arch.sve_state);

	/* Limit guest vector length to the maximum supported by the host.  */

	hyp_vcpu->vcpu.arch.sve_max_vl	= min(host_vcpu->arch.sve_max_vl, kvm_host_sve_max_vl);



	hyp_vcpu->vcpu.arch.mdcr_el2	= host_vcpu->arch.mdcr_el2;

	hyp_vcpu->vcpu.arch.hcr_el2 &= ~(HCR_TWI | HCR_TWE);

	hyp_vcpu->vcpu.arch.hcr_el2 |= READ_ONCE(host_vcpu->arch.hcr_el2) &

arch/arm64/kvm/hyp/nvhe/pkvm.c

+44 −3
Original line number Diff line number Diff line
@@ -372,6 +372,18 @@ static void unpin_host_vcpu(struct kvm_vcpu *host_vcpu) 
		hyp_unpin_shared_mem(host_vcpu, host_vcpu + 1);

}



static void unpin_host_sve_state(struct pkvm_hyp_vcpu *hyp_vcpu)

{

	void *sve_state;



	if (!vcpu_has_feature(&hyp_vcpu->vcpu, KVM_ARM_VCPU_SVE))

		return;



	sve_state = kern_hyp_va(hyp_vcpu->vcpu.arch.sve_state);

	hyp_unpin_shared_mem(sve_state,

			     sve_state + vcpu_sve_state_size(&hyp_vcpu->vcpu));

}



static void unpin_host_vcpus(struct pkvm_hyp_vcpu *hyp_vcpus[],

			     unsigned int nr_vcpus)

{
@@ -384,6 +396,7 @@ static void unpin_host_vcpus(struct pkvm_hyp_vcpu *hyp_vcpus[], 
			continue;



		unpin_host_vcpu(hyp_vcpu->host_vcpu);

		unpin_host_sve_state(hyp_vcpu);

	}

}
@@ -398,12 +411,40 @@ static void init_pkvm_hyp_vm(struct kvm *host_kvm, struct pkvm_hyp_vm *hyp_vm, 
	pkvm_init_features_from_host(hyp_vm, host_kvm);

}



static void pkvm_vcpu_init_sve(struct pkvm_hyp_vcpu *hyp_vcpu, struct kvm_vcpu *host_vcpu)

static int pkvm_vcpu_init_sve(struct pkvm_hyp_vcpu *hyp_vcpu, struct kvm_vcpu *host_vcpu)

{

	struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu;

	unsigned int sve_max_vl;

	size_t sve_state_size;

	void *sve_state;

	int ret = 0;



	if (!vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE))

	if (!vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) {

		vcpu_clear_flag(vcpu, VCPU_SVE_FINALIZED);

		return 0;

	}



	/* Limit guest vector length to the maximum supported by the host. */

	sve_max_vl = min(READ_ONCE(host_vcpu->arch.sve_max_vl), kvm_host_sve_max_vl);

	sve_state_size = sve_state_size_from_vl(sve_max_vl);

	sve_state = kern_hyp_va(READ_ONCE(host_vcpu->arch.sve_state));



	if (!sve_state || !sve_state_size) {

		ret = -EINVAL;

		goto err;

	}



	ret = hyp_pin_shared_mem(sve_state, sve_state + sve_state_size);

	if (ret)

		goto err;



	vcpu->arch.sve_state = sve_state;

	vcpu->arch.sve_max_vl = sve_max_vl;



	return 0;

err:

	clear_bit(KVM_ARM_VCPU_SVE, vcpu->kvm->arch.vcpu_features);

	return ret;

}



static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu,
@@ -432,7 +473,7 @@ static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, 
	if (ret)

		goto done;



	pkvm_vcpu_init_sve(hyp_vcpu, host_vcpu);

	ret = pkvm_vcpu_init_sve(hyp_vcpu, host_vcpu);

done:

	if (ret)

		unpin_host_vcpu(host_vcpu);