From 117c3b21d3c79af56750f18a54f2c468f30c8a45 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 18 Apr 2025 10:31:29 +0100 Subject: [PATCH 01/12] arm64: Rework checks for broken Cavium HW in the PI code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Calling into the MIDR checking framework from the PI code has recently become much harder, due to the new fancy "multi-MIDR" support that relies on tables being populated at boot time, but not that early that they are available to the PI code. There are additional issues with this framework, as the code really isn't position independend *at all*. This leads to some ugly breakages, as reported by Ada. It so appears that the only reason for the PI code to call into the MIDR checking code is to cope with The Most Broken ARM64 System Ever, aka Cavium ThunderX, which cannot deal with nG attributes that result of the combination of KASLR and KPTI as a consequence of Erratum 27456. Duplicate the check for the erratum in the PI code, removing the dependency on the bulk of the MIDR checking framework. This allows dropping that same check from kaslr_requires_kpti(), as the KPTI code already relies on the ARM64_WORKAROUND_CAVIUM_27456 cap. Fixes: c8c2647e69bed ("arm64: Make  _midr_in_range_list() an exported function") Reported-by: Ada Couprie Diaz Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/3d97e45a-23cf-419b-9b6f-140b4d88de7b@arm.com Cc: Catalin Marinas Cc: Will Deacon Cc: Shameer Kolothum Cc: Oliver Upton Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20250418093129.1755739-1-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/include/asm/mmu.h | 11 ----------- arch/arm64/kernel/cpu_errata.c | 2 +- arch/arm64/kernel/image-vars.h | 4 ---- arch/arm64/kernel/pi/map_kernel.c | 25 ++++++++++++++++++++++++- 4 files changed, 25 insertions(+), 17 deletions(-) diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index 30a29e88994b..6e8aa8e72601 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -94,17 +94,6 @@ static inline bool kaslr_requires_kpti(void) return false; } - /* - * Systems affected by Cavium erratum 24756 are incompatible - * with KPTI. - */ - if (IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) { - extern const struct midr_range cavium_erratum_27456_cpus[]; - - if (is_midr_in_range_list(cavium_erratum_27456_cpus)) - return false; - } - return true; } diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index b55f5f705750..6b0ad5070d3e 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -335,7 +335,7 @@ static const struct midr_range cavium_erratum_23154_cpus[] = { #endif #ifdef CONFIG_CAVIUM_ERRATUM_27456 -const struct midr_range cavium_erratum_27456_cpus[] = { +static const struct midr_range cavium_erratum_27456_cpus[] = { /* Cavium ThunderX, T88 pass 1.x - 2.1 */ MIDR_RANGE(MIDR_THUNDERX, 0, 0, 1, 1), /* Cavium ThunderX, T81 pass 1.0 */ diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 5e3c4b58f279..2004b4f41ade 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -47,10 +47,6 @@ PROVIDE(__pi_id_aa64smfr0_override = id_aa64smfr0_override); PROVIDE(__pi_id_aa64zfr0_override = id_aa64zfr0_override); PROVIDE(__pi_arm64_sw_feature_override = arm64_sw_feature_override); PROVIDE(__pi_arm64_use_ng_mappings = arm64_use_ng_mappings); -#ifdef CONFIG_CAVIUM_ERRATUM_27456 -PROVIDE(__pi_cavium_erratum_27456_cpus = cavium_erratum_27456_cpus); -PROVIDE(__pi_is_midr_in_range_list = is_midr_in_range_list); -#endif PROVIDE(__pi__ctype = _ctype); PROVIDE(__pi_memstart_offset_seed = memstart_offset_seed); diff --git a/arch/arm64/kernel/pi/map_kernel.c b/arch/arm64/kernel/pi/map_kernel.c index e57b043f324b..c6650cfe706c 100644 --- a/arch/arm64/kernel/pi/map_kernel.c +++ b/arch/arm64/kernel/pi/map_kernel.c @@ -207,6 +207,29 @@ static void __init map_fdt(u64 fdt) dsb(ishst); } +/* + * PI version of the Cavium Eratum 27456 detection, which makes it + * impossible to use non-global mappings. + */ +static bool __init ng_mappings_allowed(void) +{ + static const struct midr_range cavium_erratum_27456_cpus[] __initconst = { + /* Cavium ThunderX, T88 pass 1.x - 2.1 */ + MIDR_RANGE(MIDR_THUNDERX, 0, 0, 1, 1), + /* Cavium ThunderX, T81 pass 1.0 */ + MIDR_REV(MIDR_THUNDERX_81XX, 0, 0), + {}, + }; + + for (const struct midr_range *r = cavium_erratum_27456_cpus; r->model; r++) { + if (midr_is_cpu_model_range(read_cpuid_id(), r->model, + r->rv_min, r->rv_max)) + return false; + } + + return true; +} + asmlinkage void __init early_map_kernel(u64 boot_status, void *fdt) { static char const chosen_str[] __initconst = "/chosen"; @@ -246,7 +269,7 @@ asmlinkage void __init early_map_kernel(u64 boot_status, void *fdt) u64 kaslr_seed = kaslr_early_init(fdt, chosen); if (kaslr_seed && kaslr_requires_kpti()) - arm64_use_ng_mappings = true; + arm64_use_ng_mappings = ng_mappings_allowed(); kaslr_offset |= kaslr_seed & ~(MIN_KIMG_ALIGN - 1); } From 5f9e1698141a724ef63f75ee22fa9007d97de5bb Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 18 Apr 2025 13:03:08 -0400 Subject: [PATCH 02/12] KVM: arm64, x86: make kvm_arch_has_irq_bypass() inline kvm_arch_has_irq_bypass() is a small function and even though it does not appear in any *really* hot paths, it's also not entirely rare. Make it inline---it also works out nicely in preparation for using it in kvm-intel.ko and kvm-amd.ko, since the function is not currently exported. Suggested-by: Linus Torvalds Signed-off-by: Paolo Bonzini --- arch/arm64/include/asm/kvm_host.h | 5 +++++ arch/arm64/kvm/arm.c | 5 ----- arch/x86/include/asm/kvm_host.h | 6 ++++++ arch/x86/kvm/x86.c | 5 ----- 4 files changed, 11 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index e98cfe7855a6..08ba91e6fb03 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1588,4 +1588,9 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val); #define kvm_has_s1poe(k) \ (kvm_has_feat((k), ID_AA64MMFR3_EL1, S1POE, IMP)) +static inline bool kvm_arch_has_irq_bypass(void) +{ + return true; +} + #endif /* __ARM64_KVM_HOST_H__ */ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 68fec8c95fee..19ca57def629 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -2743,11 +2743,6 @@ bool kvm_arch_irqchip_in_kernel(struct kvm *kvm) return irqchip_in_kernel(kvm); } -bool kvm_arch_has_irq_bypass(void) -{ - return true; -} - int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons, struct irq_bypass_producer *prod) { diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 3bdae454a959..7bc174a1f1cb 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -2423,4 +2424,9 @@ int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages); */ #define KVM_EXIT_HYPERCALL_MBZ GENMASK_ULL(31, 1) +static inline bool kvm_arch_has_irq_bypass(void) +{ + return enable_apicv && irq_remapping_cap(IRQ_POSTING_CAP); +} + #endif /* _ASM_X86_KVM_HOST_H */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3712dde0bf9d..c1fdd527044c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -13556,11 +13556,6 @@ bool kvm_arch_has_noncoherent_dma(struct kvm *kvm) } EXPORT_SYMBOL_GPL(kvm_arch_has_noncoherent_dma); -bool kvm_arch_has_irq_bypass(void) -{ - return enable_apicv && irq_remapping_cap(IRQ_POSTING_CAP); -} - int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons, struct irq_bypass_producer *prod) { From 6560aff981ada9aec8163509a59d8f48283263d6 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 1 Apr 2025 09:18:03 -0700 Subject: [PATCH 03/12] KVM: SVM: Don't update IRTEs if APICv/AVIC is disabled Skip IRTE updates if AVIC is disabled/unsupported, as forcing the IRTE into remapped mode (kvm_vcpu_apicv_active() will never be true) is unnecessary and wasteful. The IOMMU driver is responsible for putting IRTEs into remapped mode when an IRQ is allocated by a device, long before that device is assigned to a VM. I.e. the kernel as a whole has major issues if the IRTE isn't already in remapped mode. Opportunsitically kvm_arch_has_irq_bypass() to query for APICv/AVIC, so so that all checks in KVM x86 incorporate the same information. Cc: Yosry Ahmed Cc: Jim Mattson Signed-off-by: Sean Christopherson Message-ID: <20250401161804.842968-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/avic.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 65fd245a9953..901d8d2dc169 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -898,8 +898,7 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq, struct kvm_irq_routing_table *irq_rt; int idx, ret = 0; - if (!kvm_arch_has_assigned_device(kvm) || - !irq_remapping_cap(IRQ_POSTING_CAP)) + if (!kvm_arch_has_assigned_device(kvm) || !kvm_arch_has_irq_bypass()) return 0; pr_debug("SVM: %s: host_irq=%#x, guest_irq=%#x, set=%#x\n", From 7537deda36521fa8fff9133b39c46e31893606f2 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 4 Apr 2025 12:38:16 -0700 Subject: [PATCH 04/12] KVM: SVM: Allocate IR data using atomic allocation Allocate SVM's interrupt remapping metadata using GFP_ATOMIC as svm_ir_list_add() is called with IRQs are disabled and irqfs.lock held when kvm_irq_routing_update() reacts to GSI routing changes. Fixes: 411b44ba80ab ("svm: Implements update_pi_irte hook to setup posted interrupt") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-ID: <20250404193923.1413163-2-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/avic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 901d8d2dc169..a961e6e67050 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -820,7 +820,7 @@ static int svm_ir_list_add(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi) * Allocating new amd_iommu_pi_data, which will get * add to the per-vcpu ir_list. */ - ir = kzalloc(sizeof(struct amd_svm_iommu_ir), GFP_KERNEL_ACCOUNT); + ir = kzalloc(sizeof(struct amd_svm_iommu_ir), GFP_ATOMIC | __GFP_ACCOUNT); if (!ir) { ret = -ENOMEM; goto out; From 9bcac97dc42d2f4da8229d18feb0fe2b1ce523a2 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 4 Apr 2025 12:38:17 -0700 Subject: [PATCH 05/12] KVM: x86: Reset IRTE to host control if *new* route isn't postable Restore an IRTE back to host control (remapped or posted MSI mode) if the *new* GSI route prevents posting the IRQ directly to a vCPU, regardless of the GSI routing type. Updating the IRTE if and only if the new GSI is an MSI results in KVM leaving an IRTE posting to a vCPU. The dangling IRTE can result in interrupts being incorrectly delivered to the guest, and in the worst case scenario can result in use-after-free, e.g. if the VM is torn down, but the underlying host IRQ isn't freed. Fixes: efc644048ecd ("KVM: x86: Update IRTE for posted-interrupts") Fixes: 411b44ba80ab ("svm: Implements update_pi_irte hook to setup posted interrupt") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-ID: <20250404193923.1413163-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/avic.c | 58 ++++++++++++++++++---------------- arch/x86/kvm/vmx/posted_intr.c | 28 ++++++---------- 2 files changed, 41 insertions(+), 45 deletions(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index a961e6e67050..8e09f6ae98fd 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -896,6 +896,7 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq, { struct kvm_kernel_irq_routing_entry *e; struct kvm_irq_routing_table *irq_rt; + bool enable_remapped_mode = true; int idx, ret = 0; if (!kvm_arch_has_assigned_device(kvm) || !kvm_arch_has_irq_bypass()) @@ -932,6 +933,8 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq, kvm_vcpu_apicv_active(&svm->vcpu)) { struct amd_iommu_pi_data pi; + enable_remapped_mode = false; + /* Try to enable guest_mode in IRTE */ pi.base = __sme_set(page_to_phys(svm->avic_backing_page) & AVIC_HPA_MASK); @@ -950,33 +953,6 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq, */ if (!ret && pi.is_guest_mode) svm_ir_list_add(svm, &pi); - } else { - /* Use legacy mode in IRTE */ - struct amd_iommu_pi_data pi; - - /** - * Here, pi is used to: - * - Tell IOMMU to use legacy mode for this interrupt. - * - Retrieve ga_tag of prior interrupt remapping data. - */ - pi.prev_ga_tag = 0; - pi.is_guest_mode = false; - ret = irq_set_vcpu_affinity(host_irq, &pi); - - /** - * Check if the posted interrupt was previously - * setup with the guest_mode by checking if the ga_tag - * was cached. If so, we need to clean up the per-vcpu - * ir_list. - */ - if (!ret && pi.prev_ga_tag) { - int id = AVIC_GATAG_TO_VCPUID(pi.prev_ga_tag); - struct kvm_vcpu *vcpu; - - vcpu = kvm_get_vcpu_by_id(kvm, id); - if (vcpu) - svm_ir_list_del(to_svm(vcpu), &pi); - } } if (!ret && svm) { @@ -992,6 +968,34 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq, } ret = 0; + if (enable_remapped_mode) { + /* Use legacy mode in IRTE */ + struct amd_iommu_pi_data pi; + + /** + * Here, pi is used to: + * - Tell IOMMU to use legacy mode for this interrupt. + * - Retrieve ga_tag of prior interrupt remapping data. + */ + pi.prev_ga_tag = 0; + pi.is_guest_mode = false; + ret = irq_set_vcpu_affinity(host_irq, &pi); + + /** + * Check if the posted interrupt was previously + * setup with the guest_mode by checking if the ga_tag + * was cached. If so, we need to clean up the per-vcpu + * ir_list. + */ + if (!ret && pi.prev_ga_tag) { + int id = AVIC_GATAG_TO_VCPUID(pi.prev_ga_tag); + struct kvm_vcpu *vcpu; + + vcpu = kvm_get_vcpu_by_id(kvm, id); + if (vcpu) + svm_ir_list_del(to_svm(vcpu), &pi); + } + } out: srcu_read_unlock(&kvm->irq_srcu, idx); return ret; diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 51116fe69a50..d70e5b90087d 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -297,6 +297,7 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq, { struct kvm_kernel_irq_routing_entry *e; struct kvm_irq_routing_table *irq_rt; + bool enable_remapped_mode = true; struct kvm_lapic_irq irq; struct kvm_vcpu *vcpu; struct vcpu_data vcpu_info; @@ -335,21 +336,8 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq, kvm_set_msi_irq(kvm, e, &irq); if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu) || - !kvm_irq_is_postable(&irq)) { - /* - * Make sure the IRTE is in remapped mode if - * we don't handle it in posted mode. - */ - ret = irq_set_vcpu_affinity(host_irq, NULL); - if (ret < 0) { - printk(KERN_INFO - "failed to back to remapped mode, irq: %u\n", - host_irq); - goto out; - } - + !kvm_irq_is_postable(&irq)) continue; - } vcpu_info.pi_desc_addr = __pa(vcpu_to_pi_desc(vcpu)); vcpu_info.vector = irq.vector; @@ -357,11 +345,12 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq, trace_kvm_pi_irte_update(host_irq, vcpu->vcpu_id, e->gsi, vcpu_info.vector, vcpu_info.pi_desc_addr, set); - if (set) - ret = irq_set_vcpu_affinity(host_irq, &vcpu_info); - else - ret = irq_set_vcpu_affinity(host_irq, NULL); + if (!set) + continue; + enable_remapped_mode = false; + + ret = irq_set_vcpu_affinity(host_irq, &vcpu_info); if (ret < 0) { printk(KERN_INFO "%s: failed to update PI IRTE\n", __func__); @@ -369,6 +358,9 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq, } } + if (enable_remapped_mode) + ret = irq_set_vcpu_affinity(host_irq, NULL); + ret = 0; out: srcu_read_unlock(&kvm->irq_srcu, idx); From bcda70c56f3e718465cab2aad260cf34183ce1ce Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 4 Apr 2025 12:38:18 -0700 Subject: [PATCH 06/12] KVM: x86: Explicitly treat routing entry type changes as changes Explicitly treat type differences as GSI routing changes, as comparing MSI data between two entries could get a false negative, e.g. if userspace changed the type but left the type-specific data as-is. Fixes: 515a0c79e796 ("kvm: irqfd: avoid update unmodified entries of the routing") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-ID: <20250404193923.1413163-4-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c1fdd527044c..9c98b77b7dc1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -13607,7 +13607,8 @@ int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq, bool kvm_arch_irqfd_route_changed(struct kvm_kernel_irq_routing_entry *old, struct kvm_kernel_irq_routing_entry *new) { - if (new->type != KVM_IRQ_ROUTING_MSI) + if (old->type != KVM_IRQ_ROUTING_MSI || + new->type != KVM_IRQ_ROUTING_MSI) return true; return !!memcmp(&old->msi, &new->msi, sizeof(new->msi)); From f1fb088d9cecde5c3066d8ff8846789667519b7d Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 4 Apr 2025 12:38:19 -0700 Subject: [PATCH 07/12] KVM: x86: Take irqfds.lock when adding/deleting IRQ bypass producer Take irqfds.lock when adding/deleting an IRQ bypass producer to ensure irqfd->producer isn't modified while kvm_irq_routing_update() is running. The only lock held when a producer is added/removed is irqbypass's mutex. Fixes: 872768800652 ("KVM: x86: select IRQ_BYPASS_MANAGER") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-ID: <20250404193923.1413163-5-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9c98b77b7dc1..a6829a370e6a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -13561,15 +13561,22 @@ int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons, { struct kvm_kernel_irqfd *irqfd = container_of(cons, struct kvm_kernel_irqfd, consumer); + struct kvm *kvm = irqfd->kvm; int ret; - irqfd->producer = prod; kvm_arch_start_assignment(irqfd->kvm); + + spin_lock_irq(&kvm->irqfds.lock); + irqfd->producer = prod; + ret = kvm_x86_call(pi_update_irte)(irqfd->kvm, prod->irq, irqfd->gsi, 1); if (ret) kvm_arch_end_assignment(irqfd->kvm); + spin_unlock_irq(&kvm->irqfds.lock); + + return ret; } @@ -13579,9 +13586,9 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons, int ret; struct kvm_kernel_irqfd *irqfd = container_of(cons, struct kvm_kernel_irqfd, consumer); + struct kvm *kvm = irqfd->kvm; WARN_ON(irqfd->producer != prod); - irqfd->producer = NULL; /* * When producer of consumer is unregistered, we change back to @@ -13589,12 +13596,18 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons, * when the irq is masked/disabled or the consumer side (KVM * int this case doesn't want to receive the interrupts. */ + spin_lock_irq(&kvm->irqfds.lock); + irqfd->producer = NULL; + ret = kvm_x86_call(pi_update_irte)(irqfd->kvm, prod->irq, irqfd->gsi, 0); if (ret) printk(KERN_INFO "irq bypass consumer (token %p) unregistration" " fails: %d\n", irqfd->consumer.token, ret); + spin_unlock_irq(&kvm->irqfds.lock); + + kvm_arch_end_assignment(irqfd->kvm); } From 07172206a26dcf3f0bf7c3ecaadd4242b008ea54 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 4 Apr 2025 12:38:20 -0700 Subject: [PATCH 08/12] iommu/amd: Return an error if vCPU affinity is set for non-vCPU IRTE Return -EINVAL instead of success if amd_ir_set_vcpu_affinity() is invoked without use_vapic; lying to KVM about whether or not the IRTE was configured to post IRQs is all kinds of bad. Fixes: d98de49a53e4 ("iommu/amd: Enable vAPIC interrupt remapping mode by default") Signed-off-by: Sean Christopherson Message-ID: <20250404193923.1413163-6-seanjc@google.com> Signed-off-by: Paolo Bonzini --- drivers/iommu/amd/iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index be8761bbef0f..00965518b802 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -3879,7 +3879,7 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info) * we should not modify the IRTE */ if (!dev_data || !dev_data->use_vapic) - return 0; + return -EINVAL; ir_data->cfg = irqd_cfg(data); pi_data->ir_data = ir_data; From aae251a380fe4741594368e0d7836a082b17ae3e Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 4 Apr 2025 12:38:21 -0700 Subject: [PATCH 09/12] iommu/amd: WARN if KVM attempts to set vCPU affinity without posted intrrupts WARN if KVM attempts to set vCPU affinity when posted interrupts aren't enabled, as KVM shouldn't try to enable posting when they're unsupported, and the IOMMU driver darn well should only advertise posting support when AMD_IOMMU_GUEST_IR_VAPIC() is true. Note, KVM consumes is_guest_mode only on success. Signed-off-by: Sean Christopherson Message-ID: <20250404193923.1413163-7-seanjc@google.com> Signed-off-by: Paolo Bonzini --- drivers/iommu/amd/iommu.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 00965518b802..f34209b08b4c 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -3869,6 +3869,9 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info) struct irq_2_irte *irte_info = &ir_data->irq_2_irte; struct iommu_dev_data *dev_data; + if (WARN_ON_ONCE(!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))) + return -EINVAL; + if (ir_data->iommu == NULL) return -EINVAL; @@ -3884,16 +3887,6 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info) ir_data->cfg = irqd_cfg(data); pi_data->ir_data = ir_data; - /* Note: - * SVM tries to set up for VAPIC mode, but we are in - * legacy mode. So, we force legacy mode instead. - */ - if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir)) { - pr_debug("%s: Fall back to using intr legacy remap\n", - __func__); - pi_data->is_guest_mode = false; - } - pi_data->prev_ga_tag = ir_data->cached_ga_tag; if (pi_data->is_guest_mode) { ir_data->ga_root_ptr = (pi_data->base >> 12); From 268cbfe65bb9096f78f98d1e092b1939d3caa382 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 4 Apr 2025 12:38:22 -0700 Subject: [PATCH 10/12] KVM: SVM: WARN if an invalid posted interrupt IRTE entry is added Now that the AMD IOMMU doesn't signal success incorrectly, WARN if KVM attempts to track an AMD IRTE entry without metadata. Signed-off-by: Sean Christopherson Message-ID: <20250404193923.1413163-8-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/avic.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 8e09f6ae98fd..7338879d1c0c 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -796,12 +796,15 @@ static int svm_ir_list_add(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi) struct amd_svm_iommu_ir *ir; u64 entry; + if (WARN_ON_ONCE(!pi->ir_data)) + return -EINVAL; + /** * In some cases, the existing irte is updated and re-set, * so we need to check here if it's already been * added * to the ir_list. */ - if (pi->ir_data && (pi->prev_ga_tag != 0)) { + if (pi->prev_ga_tag) { struct kvm *kvm = svm->vcpu.kvm; u32 vcpu_id = AVIC_GATAG_TO_VCPUID(pi->prev_ga_tag); struct kvm_vcpu *prev_vcpu = kvm_get_vcpu_by_id(kvm, vcpu_id); From ca4f113b0b4c2de6ffb438d5d0ebb7337877c911 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Tue, 15 Apr 2025 13:48:20 +0300 Subject: [PATCH 11/12] KVM: x86: Do not use kvm_rip_read() unconditionally in KVM tracepoints Not all VMs allow access to RIP. Check guest_state_protected before calling kvm_rip_read(). This avoids, for example, hitting WARN_ON_ONCE in vt_cache_reg() for TDX VMs. Fixes: 81bf912b2c15 ("KVM: TDX: Implement TDX vcpu enter/exit path") Signed-off-by: Adrian Hunter Message-ID: <20250415104821.247234-2-adrian.hunter@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/trace.h | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h index ccda95e53f62..ba736cbb0587 100644 --- a/arch/x86/kvm/trace.h +++ b/arch/x86/kvm/trace.h @@ -11,6 +11,13 @@ #undef TRACE_SYSTEM #define TRACE_SYSTEM kvm +#ifdef CREATE_TRACE_POINTS +#define tracing_kvm_rip_read(vcpu) ({ \ + typeof(vcpu) __vcpu = vcpu; \ + __vcpu->arch.guest_state_protected ? 0 : kvm_rip_read(__vcpu); \ + }) +#endif + /* * Tracepoint for guest mode entry. */ @@ -28,7 +35,7 @@ TRACE_EVENT(kvm_entry, TP_fast_assign( __entry->vcpu_id = vcpu->vcpu_id; - __entry->rip = kvm_rip_read(vcpu); + __entry->rip = tracing_kvm_rip_read(vcpu); __entry->immediate_exit = force_immediate_exit; kvm_x86_call(get_entry_info)(vcpu, &__entry->intr_info, @@ -319,7 +326,7 @@ TRACE_EVENT(name, \ ), \ \ TP_fast_assign( \ - __entry->guest_rip = kvm_rip_read(vcpu); \ + __entry->guest_rip = tracing_kvm_rip_read(vcpu); \ __entry->isa = isa; \ __entry->vcpu_id = vcpu->vcpu_id; \ __entry->requests = READ_ONCE(vcpu->requests); \ @@ -423,7 +430,7 @@ TRACE_EVENT(kvm_page_fault, TP_fast_assign( __entry->vcpu_id = vcpu->vcpu_id; - __entry->guest_rip = kvm_rip_read(vcpu); + __entry->guest_rip = tracing_kvm_rip_read(vcpu); __entry->fault_address = fault_address; __entry->error_code = error_code; ), From 38e93267ca6807fc34288ce1a9c610bf219fc0e0 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Tue, 15 Apr 2025 13:48:21 +0300 Subject: [PATCH 12/12] KVM: x86: Do not use kvm_rip_read() unconditionally for KVM_PROFILING Not all VMs allow access to RIP. Check guest_state_protected before calling kvm_rip_read(). This avoids, for example, hitting WARN_ON_ONCE in vt_cache_reg() for TDX VMs. Fixes: 81bf912b2c15 ("KVM: TDX: Implement TDX vcpu enter/exit path") Signed-off-by: Adrian Hunter Message-ID: <20250415104821.247234-3-adrian.hunter@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a6829a370e6a..df5b99ea1f18 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11098,7 +11098,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) /* * Profile KVM exit RIPs: */ - if (unlikely(prof_on == KVM_PROFILING)) { + if (unlikely(prof_on == KVM_PROFILING && + !vcpu->arch.guest_state_protected)) { unsigned long rip = kvm_rip_read(vcpu); profile_hit(KVM_PROFILING, (void *)rip); }