From c4cdbaf9d81c8387da8b9b91567d4b0eb1b8a549 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 11 Jun 2025 15:45:24 -0700 Subject: [PATCH] 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 Reviewed-by: Joao Martins Reviewed-by: Vasant Hegde Tested-by: Sairaj Kodilkar Link: https://lore.kernel.org/r/20250611224604.313496-23-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/avic.c | 7 +++++-- drivers/iommu/amd/iommu.c | 2 +- include/linux/amd-iommu.h | 2 -- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 375a29022000e..d95742faae110 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -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; diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index ed96050d4933b..bdfb57af7111c 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -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); diff --git a/include/linux/amd-iommu.h b/include/linux/amd-iommu.h index 1f9b13d803c5d..deeefc92a5cf5 100644 --- a/include/linux/amd-iommu.h +++ b/include/linux/amd-iommu.h @@ -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; -- 2.47.2