KVM: Pass new routing entries and irqfd when updating IRTEs

When updating IRTEs in response to a GSI routing or IRQ bypass change,
pass the new/current routing information along with the associated irqfd.
This will allow KVM x86 to harden, simplify, and deduplicate its code.

Since adding/removing a bypass producer is now conveniently protected with
irqfds.lock, i.e. can't run concurrently with kvm_irq_routing_update(),
use the routing information cached in the irqfd instead of looking up
the information in the current GSI routing tables.

Opportunistically convert an existing printk() to pr_info() and put its
string onto a single line (old code that strictly adhered to 80 chars).

Link: https://lore.kernel.org/r/20250611224604.313496-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 38a91bb5d4c75145daf890ec988288bdcec0ab3e..a9a39e0375f7a09c9257f1879898c2d2b24186d3 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -2771,8 +2771,9 @@ bool kvm_arch_irqfd_route_changed(struct kvm_kernel_irq_routing_entry *old,
        return memcmp(&old->msi, &new->msi, sizeof(new->msi));
 }
 
-int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq,
-                                 uint32_t guest_irq, bool set)
+int kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
+                                 struct kvm_kernel_irq_routing_entry *old,
+                                 struct kvm_kernel_irq_routing_entry *new)
 {
        /*
         * Remapping the vLPI requires taking the its_lock mutex to resolve
@@ -2781,7 +2782,7 @@ int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq,
         *
         * Unmap the vLPI and fall back to software LPI injection.
         */
-       return kvm_vgic_v4_unset_forwarding(kvm, host_irq);
+       return kvm_vgic_v4_unset_forwarding(irqfd->kvm, irqfd->producer->irq);
 }
 
 void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *cons)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 44fd9ccc06248fe7c0fd46b24fa88c52f358c8c3..2a14564dd08a57eccdf812323783a041f89b928a 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -297,6 +297,7 @@ enum x86_intercept_stage;
  */
 #define KVM_APIC_PV_EOI_PENDING        1
 
+struct kvm_kernel_irqfd;
 struct kvm_kernel_irq_routing_entry;
 
 /*
@@ -1845,8 +1846,9 @@ struct kvm_x86_ops {
        void (*vcpu_blocking)(struct kvm_vcpu *vcpu);
        void (*vcpu_unblocking)(struct kvm_vcpu *vcpu);
 
-       int (*pi_update_irte)(struct kvm *kvm, unsigned int host_irq,
-                             uint32_t guest_irq, bool set);
+       int (*pi_update_irte)(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
+                             unsigned int host_irq, uint32_t guest_irq,
+                             struct kvm_kernel_irq_routing_entry *new);
        void (*pi_start_assignment)(struct kvm *kvm);
        void (*apicv_pre_state_restore)(struct kvm_vcpu *vcpu);
        void (*apicv_post_state_restore)(struct kvm_vcpu *vcpu);

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 067f8e3f5a0dc5b6d9f8655ade826697e3a28378..49b73907de92c0b303393464415e8c646d89e2c8 100644 (file)
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -18,6 +18,7 @@
 #include <linux/hashtable.h>
 #include <linux/amd-iommu.h>
 #include <linux/kvm_host.h>
+#include <linux/kvm_irqfd.h>
 
 #include <asm/irq_remapping.h>
 #include <asm/msr.h>
@@ -886,21 +887,14 @@ get_pi_vcpu_info(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
        return 0;
 }
 
-/*
- * avic_pi_update_irte - set IRTE for Posted-Interrupts
- *
- * @kvm: kvm
- * @host_irq: host irq of the interrupt
- * @guest_irq: gsi of the interrupt
- * @set: set or unset PI
- * returns 0 on success, < 0 on failure
- */
-int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
-                       uint32_t guest_irq, bool set)
+int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
+                       unsigned int host_irq, uint32_t guest_irq,
+                       struct kvm_kernel_irq_routing_entry *new)
 {
        struct kvm_kernel_irq_routing_entry *e;
        struct kvm_irq_routing_table *irq_rt;
        bool enable_remapped_mode = true;
+       bool set = !!new;
        int idx, ret = 0;
 
        if (!kvm_arch_has_assigned_device(kvm) || !kvm_arch_has_irq_bypass())
@@ -926,6 +920,8 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
                if (e->type != KVM_IRQ_ROUTING_MSI)
                        continue;
 
+               WARN_ON_ONCE(new && memcmp(e, new, sizeof(*new)));
+
                /**
                 * Here, we setup with legacy mode in the following cases:
                 * 1. When cannot target interrupt to a specific vcpu.

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index e6f3c6a153a0cf2ce20cd4b3ab99b87b544da5ab..b35fce30d92314cbbb2d2ffe485093df4652bd7c 100644 (file)
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -736,8 +736,9 @@ void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
 void avic_vcpu_put(struct kvm_vcpu *vcpu);
 void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu);
 void avic_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu);
-int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
-                       uint32_t guest_irq, bool set);
+int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
+                       unsigned int host_irq, uint32_t guest_irq,
+                       struct kvm_kernel_irq_routing_entry *new);
 void avic_vcpu_blocking(struct kvm_vcpu *vcpu);
 void avic_vcpu_unblocking(struct kvm_vcpu *vcpu);
 void avic_ring_doorbell(struct kvm_vcpu *vcpu);

diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c
index 5c615e5845bf04788c1b41831a8126f76bf55c59..110fb19848ab40fbf54125e9c7e7d5527e043fa7 100644 (file)
--- a/arch/x86/kvm/vmx/posted_intr.c
+++ b/arch/x86/kvm/vmx/posted_intr.c
@@ -2,6 +2,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/kvm_host.h>
+#include <linux/kvm_irqfd.h>
 
 #include <asm/irq_remapping.h>
 #include <asm/cpu.h>
@@ -294,17 +295,9 @@ void vmx_pi_start_assignment(struct kvm *kvm)
        kvm_make_all_cpus_request(kvm, KVM_REQ_UNBLOCK);
 }
 
-/*
- * vmx_pi_update_irte - set IRTE for Posted-Interrupts
- *
- * @kvm: kvm
- * @host_irq: host irq of the interrupt
- * @guest_irq: gsi of the interrupt
- * @set: set or unset PI
- * returns 0 on success, < 0 on failure
- */
-int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
-                      uint32_t guest_irq, bool set)
+int vmx_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
+                      unsigned int host_irq, uint32_t guest_irq,
+                      struct kvm_kernel_irq_routing_entry *new)
 {
        struct kvm_kernel_irq_routing_entry *e;
        struct kvm_irq_routing_table *irq_rt;
@@ -312,6 +305,7 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
        struct kvm_lapic_irq irq;
        struct kvm_vcpu *vcpu;
        struct vcpu_data vcpu_info;
+       bool set = !!new;
        int idx, ret = 0;
 
        if (!vmx_can_use_vtd_pi(kvm))
@@ -329,6 +323,9 @@ int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
        hlist_for_each_entry(e, &irq_rt->map[guest_irq], link) {
                if (e->type != KVM_IRQ_ROUTING_MSI)
                        continue;
+
+               WARN_ON_ONCE(new && memcmp(e, new, sizeof(*new)));
+
                /*
                 * VT-d PI cannot support posting multicast/broadcast
                 * interrupts to a vCPU, we still use interrupt remapping

diff --git a/arch/x86/kvm/vmx/posted_intr.h b/arch/x86/kvm/vmx/posted_intr.h
index 80499ea0e674397193948d7e8059bbf7a57179a6..a94afcb55f7ffb1a9b3a37b6e40bc4a84e76056a 100644 (file)
--- a/arch/x86/kvm/vmx/posted_intr.h
+++ b/arch/x86/kvm/vmx/posted_intr.h
@@ -3,6 +3,9 @@
 #define __KVM_X86_VMX_POSTED_INTR_H
 
 #include <linux/bitmap.h>
+#include <linux/find.h>
+#include <linux/kvm_host.h>
+
 #include <asm/posted_intr.h>
 
 void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu);
@@ -11,8 +14,9 @@ void pi_wakeup_handler(void);
 void __init pi_init_cpu(int cpu);
 void pi_apicv_pre_state_restore(struct kvm_vcpu *vcpu);
 bool pi_has_pending_interrupt(struct kvm_vcpu *vcpu);
-int vmx_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
-                      uint32_t guest_irq, bool set);
+int vmx_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
+                      unsigned int host_irq, uint32_t guest_irq,
+                      struct kvm_kernel_irq_routing_entry *new);
 void vmx_pi_start_assignment(struct kvm *kvm);
 
 static inline int pi_find_highest_vector(struct pi_desc *pi_desc)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 02237dbb7f322e8d0be8f6396504e7ff2981f34d..e1304b002062c603fa3a8383074d2970c2fdcffc 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13507,31 +13507,31 @@ 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;
+       int ret = 0;
 
        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);
-
+       if (irqfd->irq_entry.type == KVM_IRQ_ROUTING_MSI) {
+               ret = kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, prod->irq,
+                                                  irqfd->gsi, &irqfd->irq_entry);
+               if (ret)
+                       kvm_arch_end_assignment(irqfd->kvm);
+       }
        spin_unlock_irq(&kvm->irqfds.lock);
 
-
        return ret;
 }
 
 void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
                                      struct irq_bypass_producer *prod)
 {
-       int ret;
        struct kvm_kernel_irqfd *irqfd =
                container_of(cons, struct kvm_kernel_irqfd, consumer);
        struct kvm *kvm = irqfd->kvm;
+       int ret;
 
        WARN_ON(irqfd->producer != prod);
 
@@ -13544,11 +13544,13 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
        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 (eventfd %p) unregistration"
-                      " fails: %d\n", irqfd->consumer.eventfd, ret);
+       if (irqfd->irq_entry.type == KVM_IRQ_ROUTING_MSI) {
+               ret = kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, prod->irq,
+                                                  irqfd->gsi, NULL);
+               if (ret)
+                       pr_info("irq bypass consumer (eventfd %p) unregistration fails: %d\n",
+                               irqfd->consumer.eventfd, ret);
+       }
 
        spin_unlock_irq(&kvm->irqfds.lock);
 
@@ -13556,10 +13558,12 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
        kvm_arch_end_assignment(irqfd->kvm);
 }
 
-int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq,
-                                  uint32_t guest_irq, bool set)
+int kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
+                                 struct kvm_kernel_irq_routing_entry *old,
+                                 struct kvm_kernel_irq_routing_entry *new)
 {
-       return kvm_x86_call(pi_update_irte)(kvm, host_irq, guest_irq, set);
+       return kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, irqfd->producer->irq,
+                                           irqfd->gsi, new);
 }
 
 bool kvm_arch_irqfd_route_changed(struct kvm_kernel_irq_routing_entry *old,

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 3b5575d0b5744bf990ffbe49ba7ae615bccd03ca..a4160c1c0c6bb99974e9f6e9e3b2421e05eaa3ed 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2401,6 +2401,8 @@ struct kvm_vcpu *kvm_get_running_vcpu(void);
 struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);
 
 #if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS)
+struct kvm_kernel_irqfd;
+
 bool kvm_arch_has_irq_bypass(void);
 int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *,
                           struct irq_bypass_producer *);
@@ -2408,8 +2410,9 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *,
                           struct irq_bypass_producer *);
 void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *);
 void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *);
-int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq,
-                                 uint32_t guest_irq, bool set);
+int kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
+                                 struct kvm_kernel_irq_routing_entry *old,
+                                 struct kvm_kernel_irq_routing_entry *new);
 bool kvm_arch_irqfd_route_changed(struct kvm_kernel_irq_routing_entry *,
                                  struct kvm_kernel_irq_routing_entry *);
 #endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 5bc6abe3074889a94a3f7c27861dd3c96f902092..bd1766da689585ac6f6891f4392342818ecee3f2 100644 (file)
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -285,9 +285,9 @@ void __attribute__((weak)) kvm_arch_irq_bypass_start(
 {
 }
 
-int  __attribute__((weak)) kvm_arch_update_irqfd_routing(
-                               struct kvm *kvm, unsigned int host_irq,
-                               uint32_t guest_irq, bool set)
+int __weak kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
+                                        struct kvm_kernel_irq_routing_entry *old,
+                                        struct kvm_kernel_irq_routing_entry *new)
 {
        return 0;
 }
@@ -618,9 +618,8 @@ void kvm_irq_routing_update(struct kvm *kvm)
 #if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS)
                if (irqfd->producer &&
                    kvm_arch_irqfd_route_changed(&old, &irqfd->irq_entry)) {
-                       int ret = kvm_arch_update_irqfd_routing(
-                                       irqfd->kvm, irqfd->producer->irq,
-                                       irqfd->gsi, 1);
+                       int ret = kvm_arch_update_irqfd_routing(irqfd, &old, &irqfd->irq_entry);
+
                        WARN_ON(ret);
                }
 #endif