Commit c4cdbaf9 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

iommu/amd: KVM: SVM: Use pi_desc_addr to derive ga_root_ptr 



Use vcpu_data.pi_desc_addr instead of amd_iommu_pi_data.base to get the
GA root pointer.  KVM is the only source of amd_iommu_pi_data.base, and
KVM's one and only path for writing amd_iommu_pi_data.base computes the
exact same value for vcpu_data.pi_desc_addr and amd_iommu_pi_data.base,
and fills amd_iommu_pi_data.base if and only if vcpu_data.pi_desc_addr is
valid, i.e. amd_iommu_pi_data.base is fully redundant.

Cc: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: default avatarJoao Martins <joao.m.martins@oracle.com>
Reviewed-by: default avatarVasant Hegde <vasant.hegde@amd.com>
Tested-by: default avatarSairaj Kodilkar <sarunkod@amd.com>
Link: https://lore.kernel.org/r/20250611224604.313496-23-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 52d826c9

arch/x86/kvm/svm/avic.c

+5 −2
Original line number Diff line number Diff line
@@ -894,8 +894,11 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm, 


			enable_remapped_mode = false;



			/* Try to enable guest_mode in IRTE */

			pi.base = avic_get_backing_page_address(svm);

			/*

			 * Try to enable guest_mode in IRTE.  Note, the address

			 * of the vCPU's AVIC backing page is passed to the

			 * IOMMU via vcpu_info->pi_desc_addr.

			 */

			pi.ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id,

						     svm->vcpu.vcpu_id);

			pi.is_guest_mode = true;

drivers/iommu/amd/iommu.c

+1 −1
Original line number Diff line number Diff line
@@ -3888,7 +3888,7 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info) 
	pi_data->ir_data = ir_data;



	if (pi_data->is_guest_mode) {

		ir_data->ga_root_ptr = (pi_data->base >> 12);

		ir_data->ga_root_ptr = (vcpu_pi_info->pi_desc_addr >> 12);

		ir_data->ga_vector = vcpu_pi_info->vector;

		ir_data->ga_tag = pi_data->ga_tag;

		ret = amd_iommu_activate_guest_mode(ir_data);

include/linux/amd-iommu.h

+0 −2
Original line number Diff line number Diff line
@@ -19,8 +19,6 @@ struct amd_iommu; 
 */

struct amd_iommu_pi_data {

	u32 ga_tag;

	u64 base;



	bool is_guest_mode;

	struct vcpu_data *vcpu_data;

	void *ir_data;