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Peter Anvin" , x86@kernel.org, Maxim Levitsky , Randy Dunlap , Paolo Bonzini , Will Deacon , Oliver Upton , Kunkun Jiang , Jing Zhang , Albert Ou , Keisuke Nishimura , Anup Patel , Catalin Marinas , Atish Patra , kvmarm@lists.linux.dev, Waiman Long , Boqun Feng , linux-arm-kernel@lists.infradead.org, Peter Zijlstra , Dave Hansen , Paul Walmsley , Suzuki K Poulose , Zenghui Yu , Sebastian Ott , Andre Przywara , Ingo Molnar , Alexandre Ghiti , Bjorn Helgaas , Palmer Dabbelt , Joey Gouly , Borislav Petkov , Sean Christopherson , Marc Zyngier , Alexander Potapenko , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Shusen Li , kvm-riscv@lists.infradead.org Subject: [PATCH v3 4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it Date: Wed, 30 Apr 2025 16:23:11 -0400 Message-ID: <20250430202311.364641-5-mlevitsk@redhat.com> In-Reply-To: <20250430202311.364641-1-mlevitsk@redhat.com> References: <20250430202311.364641-1-mlevitsk@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" Implement kvm_lock_all_vcpus() and use it instead of sev own sev_{lock|unlock}_vcpus_for_migration(). Suggested-by: Paolo Bonzini Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/sev.c | 72 +++------------------------------------- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 25 ++++++++++++++ 3 files changed, 30 insertions(+), 68 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 0bc708ee2788..16db6179013d 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1882,70 +1882,6 @@ static void sev_unlock_two_vms(struct kvm *dst_kvm, = struct kvm *src_kvm) atomic_set_release(&src_sev->migration_in_progress, 0); } =20 -/* vCPU mutex subclasses. */ -enum sev_migration_role { - SEV_MIGRATION_SOURCE =3D 0, - SEV_MIGRATION_TARGET, - SEV_NR_MIGRATION_ROLES, -}; - -static int sev_lock_vcpus_for_migration(struct kvm *kvm, - enum sev_migration_role role) -{ - struct kvm_vcpu *vcpu; - unsigned long i, j; - - kvm_for_each_vcpu(i, vcpu, kvm) { - if (mutex_lock_killable_nested(&vcpu->mutex, role)) - goto out_unlock; - -#ifdef CONFIG_PROVE_LOCKING - if (!i) - /* - * Reset the role to one that avoids colliding with - * the role used for the first vcpu mutex. - */ - role =3D SEV_NR_MIGRATION_ROLES; - else - mutex_release(&vcpu->mutex.dep_map, _THIS_IP_); -#endif - } - - return 0; - -out_unlock: - - kvm_for_each_vcpu(j, vcpu, kvm) { - if (i =3D=3D j) - break; - -#ifdef CONFIG_PROVE_LOCKING - if (j) - mutex_acquire(&vcpu->mutex.dep_map, role, 0, _THIS_IP_); -#endif - - mutex_unlock(&vcpu->mutex); - } - return -EINTR; -} - -static void sev_unlock_vcpus_for_migration(struct kvm *kvm) -{ - struct kvm_vcpu *vcpu; - unsigned long i; - bool first =3D true; - - kvm_for_each_vcpu(i, vcpu, kvm) { - if (first) - first =3D false; - else - mutex_acquire(&vcpu->mutex.dep_map, - SEV_NR_MIGRATION_ROLES, 0, _THIS_IP_); - - mutex_unlock(&vcpu->mutex); - } -} - static void sev_migrate_from(struct kvm *dst_kvm, struct kvm *src_kvm) { struct kvm_sev_info *dst =3D to_kvm_sev_info(dst_kvm); @@ -2083,10 +2019,10 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, u= nsigned int source_fd) charged =3D true; } =20 - ret =3D sev_lock_vcpus_for_migration(kvm, SEV_MIGRATION_SOURCE); + ret =3D kvm_lock_all_vcpus(kvm); if (ret) goto out_dst_cgroup; - ret =3D sev_lock_vcpus_for_migration(source_kvm, SEV_MIGRATION_TARGET); + ret =3D kvm_lock_all_vcpus(source_kvm); if (ret) goto out_dst_vcpu; =20 @@ -2100,9 +2036,9 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, uns= igned int source_fd) ret =3D 0; =20 out_source_vcpu: - sev_unlock_vcpus_for_migration(source_kvm); + kvm_unlock_all_vcpus(source_kvm); out_dst_vcpu: - sev_unlock_vcpus_for_migration(kvm); + kvm_unlock_all_vcpus(kvm); out_dst_cgroup: /* Operates on the source on success, on the destination on failure. */ if (charged) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 10d6652c7aa0..a6140415c693 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1016,6 +1016,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu_by_id(str= uct kvm *kvm, int id) void kvm_destroy_vcpus(struct kvm *kvm); =20 int kvm_trylock_all_vcpus(struct kvm *kvm); +int kvm_lock_all_vcpus(struct kvm *kvm); void kvm_unlock_all_vcpus(struct kvm *kvm); =20 void vcpu_load(struct kvm_vcpu *vcpu); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 834f08dfa24c..9211b07b0565 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1392,6 +1392,31 @@ int kvm_trylock_all_vcpus(struct kvm *kvm) } EXPORT_SYMBOL_GPL(kvm_trylock_all_vcpus); =20 +/* + * Lock all of the VM's vCPUs. + * Assumes that the kvm->lock is held. + * Returns -EINTR if the process is killed. + */ +int kvm_lock_all_vcpus(struct kvm *kvm) +{ + struct kvm_vcpu *vcpu; + unsigned long i, j; + + kvm_for_each_vcpu(i, vcpu, kvm) + if (mutex_lock_killable_nest_lock(&vcpu->mutex, &kvm->lock)) + goto out_unlock; + return 0; + +out_unlock: + kvm_for_each_vcpu(j, vcpu, kvm) { + if (i =3D=3D j) + break; + mutex_unlock(&vcpu->mutex); + } + return -EINTR; +} +EXPORT_SYMBOL_GPL(kvm_lock_all_vcpus); + void kvm_unlock_all_vcpus(struct kvm *kvm) { struct kvm_vcpu *vcpu; --=20 2.46.0