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([85.107.101.138]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47a9de1d91bsm26696110f8f.4.2026.07.06.01.13.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Jul 2026 01:13:37 -0700 (PDT) From: Furkan Caliskan To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, dwmw2@infradead.org, paul@xen.org, xen-devel@lists.xenproject.org, Furkan Caliskan Subject: [PATCH] KVM: x86/xen: Convert evtchn_ports from IDR to XArray Date: Mon, 6 Jul 2026 11:13:11 +0300 Message-Id: <20260706081311.13633-1-frn1furkan10@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit IDR is deprecated in favor of XArray: see Documentation/core-api/idr.rst. Convert evtchn_ports accordingly. kvm_xen_eventfd_assign()'s single-slot idr_alloc() becomes xa_insert(), since it was really an insert-at-index, not an allocation: -EBUSY replaces -ENOSPC, still mapped to -EEXIST. kvm_xen_hcall_evtchn_send() drops its explicit rcu_read_lock(), since xa_load() takes its own RCU read-side section internally. evtchnfd's lifetime is still guaranteed by kvm->srcu. xen_lock is left in place: it protects state beyond the map itself. Signed-off-by: Furkan Caliskan --- arch/x86/include/asm/kvm_host.h | 3 ++- arch/x86/kvm/xen.c | 34 ++++++++++++++++----------------- 2 files changed, 18 insertions(+), 19 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index d8700eb848b4..6c8542b32313 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -1290,7 +1291,7 @@ struct kvm_xen { bool runstate_update_flag; u8 upcall_vector; struct gfn_to_pfn_cache shinfo_cache; - struct idr evtchn_ports; + struct xarray evtchn_ports; unsigned long poll_mask[BITS_TO_LONGS(KVM_MAX_VCPUS)]; struct kvm_xen_hvm_config hvm_config; diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 694b31c1fcc9..754191e3bef7 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -2072,7 +2072,7 @@ static int kvm_xen_eventfd_update(struct kvm *kvm, /* Protect writes to evtchnfd as well as the idr lookup. */ mutex_lock(&kvm->arch.xen.xen_lock); - evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port); + evtchnfd = xa_load(&kvm->arch.xen.evtchn_ports, port); ret = -ENOENT; if (!evtchnfd) @@ -2166,13 +2166,13 @@ static int kvm_xen_eventfd_assign(struct kvm *kvm, } mutex_lock(&kvm->arch.xen.xen_lock); - ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1, + ret = xa_insert(&kvm->arch.xen.evtchn_ports, port, evtchnfd, GFP_KERNEL); mutex_unlock(&kvm->arch.xen.xen_lock); - if (ret >= 0) + if (!ret) return 0; - if (ret == -ENOSPC) + if (ret == -EBUSY) ret = -EEXIST; out: if (eventfd) @@ -2187,7 +2187,7 @@ static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port) struct evtchnfd *evtchnfd; mutex_lock(&kvm->arch.xen.xen_lock); - evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port); + evtchnfd = xa_erase(&kvm->arch.xen.evtchn_ports, port); mutex_unlock(&kvm->arch.xen.xen_lock); if (!evtchnfd) @@ -2203,7 +2203,7 @@ static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port) static int kvm_xen_eventfd_reset(struct kvm *kvm) { struct evtchnfd *evtchnfd, **all_evtchnfds; - int i; + unsigned long i; int n = 0; mutex_lock(&kvm->arch.xen.xen_lock); @@ -2213,7 +2213,7 @@ static int kvm_xen_eventfd_reset(struct kvm *kvm) * critical section, first collect all the evtchnfd objects * in an array as they are removed from evtchn_ports. */ - idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) + xa_for_each(&kvm->arch.xen.evtchn_ports, i, evtchnfd) n++; all_evtchnfds = kmalloc_objs(struct evtchnfd *, n); @@ -2223,9 +2223,9 @@ static int kvm_xen_eventfd_reset(struct kvm *kvm) } n = 0; - idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) { + xa_for_each(&kvm->arch.xen.evtchn_ports, i, evtchnfd) { all_evtchnfds[n++] = evtchnfd; - idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port); + xa_erase(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port); } mutex_unlock(&kvm->arch.xen.xen_lock); @@ -2276,12 +2276,10 @@ static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r) } /* - * evtchnfd is protected by kvm->srcu; the idr lookup instead - * is protected by RCU. + * evtchnfd is protected by kvm->srcu; the xa_load is RCU-safe + * internally, no explicit rcu_read_lock() needed. */ - rcu_read_lock(); - evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port); - rcu_read_unlock(); + evtchnfd = xa_load(&vcpu->kvm->arch.xen.evtchn_ports, send.port); if (!evtchnfd) return false; @@ -2328,23 +2326,23 @@ void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu) void kvm_xen_init_vm(struct kvm *kvm) { mutex_init(&kvm->arch.xen.xen_lock); - idr_init(&kvm->arch.xen.evtchn_ports); + xa_init(&kvm->arch.xen.evtchn_ports); kvm_gpc_init(&kvm->arch.xen.shinfo_cache, kvm); } void kvm_xen_destroy_vm(struct kvm *kvm) { struct evtchnfd *evtchnfd; - int i; + unsigned long i; kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache); - idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) { + xa_for_each(&kvm->arch.xen.evtchn_ports, i, evtchnfd) { if (!evtchnfd->deliver.port.port) eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx); kfree(evtchnfd); } - idr_destroy(&kvm->arch.xen.evtchn_ports); + xa_destroy(&kvm->arch.xen.evtchn_ports); if (kvm->arch.xen.hvm_config.msr) static_branch_slow_dec_deferred(&kvm_xen_enabled); -- 2.34.1