From 01ad29d224ff73bc4e16e0ef9ece17f28598c4a4 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 7 Dec 2023 15:11:57 +0000 Subject: [PATCH 1/6] KVM: arm64: vgic: Simplify kvm_vgic_destroy() When destroying a vgic, we have rather cumbersome rules about when slots_lock and config_lock are held, resulting in fun buglets. The first port of call is to simplify kvm_vgic_map_resources() so that there is only one call to kvm_vgic_destroy() instead of two, with the second only holding half of the locks. For that, we kill the non-locking primitive and move the call outside of the locking altogether. This doesn't change anything (we re-acquire the locks and teardown the whole vgic), and simplifies the code significantly. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20231207151201.3028710-2-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/vgic/vgic-init.c | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c index c8c3cb812783..ad7e86879eb9 100644 --- a/arch/arm64/kvm/vgic/vgic-init.c +++ b/arch/arm64/kvm/vgic/vgic-init.c @@ -382,26 +382,24 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF; } -static void __kvm_vgic_destroy(struct kvm *kvm) +void kvm_vgic_destroy(struct kvm *kvm) { struct kvm_vcpu *vcpu; unsigned long i; - lockdep_assert_held(&kvm->arch.config_lock); + mutex_lock(&kvm->slots_lock); vgic_debug_destroy(kvm); kvm_for_each_vcpu(i, vcpu, kvm) kvm_vgic_vcpu_destroy(vcpu); - kvm_vgic_dist_destroy(kvm); -} - -void kvm_vgic_destroy(struct kvm *kvm) -{ mutex_lock(&kvm->arch.config_lock); - __kvm_vgic_destroy(kvm); + + kvm_vgic_dist_destroy(kvm); + mutex_unlock(&kvm->arch.config_lock); + mutex_unlock(&kvm->slots_lock); } /** @@ -469,25 +467,26 @@ int kvm_vgic_map_resources(struct kvm *kvm) type = VGIC_V3; } - if (ret) { - __kvm_vgic_destroy(kvm); + if (ret) goto out; - } + dist->ready = true; dist_base = dist->vgic_dist_base; mutex_unlock(&kvm->arch.config_lock); ret = vgic_register_dist_iodev(kvm, dist_base, type); - if (ret) { + if (ret) kvm_err("Unable to register VGIC dist MMIO regions\n"); - kvm_vgic_destroy(kvm); - } - mutex_unlock(&kvm->slots_lock); - return ret; + goto out_slots; out: mutex_unlock(&kvm->arch.config_lock); +out_slots: mutex_unlock(&kvm->slots_lock); + + if (ret) + kvm_vgic_destroy(kvm); + return ret; } From d26b9cb33c2d1ba68d1f26bb06c40300f16a3799 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 7 Dec 2023 15:11:58 +0000 Subject: [PATCH 2/6] KVM: arm64: vgic: Add a non-locking primitive for kvm_vgic_vcpu_destroy() As we are going to need to call into kvm_vgic_vcpu_destroy() without prior holding of the slots_lock, introduce __kvm_vgic_vcpu_destroy() as a non-locking primitive of kvm_vgic_vcpu_destroy(). Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20231207151201.3028710-3-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/vgic/vgic-init.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c index ad7e86879eb9..a86f300321a7 100644 --- a/arch/arm64/kvm/vgic/vgic-init.c +++ b/arch/arm64/kvm/vgic/vgic-init.c @@ -368,7 +368,7 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm) vgic_v4_teardown(kvm); } -void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) +static void __kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) { struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; @@ -382,6 +382,15 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF; } +void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) +{ + struct kvm *kvm = vcpu->kvm; + + mutex_lock(&kvm->slots_lock); + __kvm_vgic_vcpu_destroy(vcpu); + mutex_unlock(&kvm->slots_lock); +} + void kvm_vgic_destroy(struct kvm *kvm) { struct kvm_vcpu *vcpu; @@ -392,7 +401,7 @@ void kvm_vgic_destroy(struct kvm *kvm) vgic_debug_destroy(kvm); kvm_for_each_vcpu(i, vcpu, kvm) - kvm_vgic_vcpu_destroy(vcpu); + __kvm_vgic_vcpu_destroy(vcpu); mutex_lock(&kvm->arch.config_lock); From 02e3858f08faabab9503ae2911cf7c7e27702257 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 7 Dec 2023 15:11:59 +0000 Subject: [PATCH 3/6] KVM: arm64: vgic: Force vcpu vgic teardown on vcpu destroy When failing to create a vcpu because (for example) it has a duplicate vcpu_id, we destroy the vcpu. Amusingly, this leaves the redistributor registered with the KVM_MMIO bus. This is no good, and we should properly clean the mess. Force a teardown of the vgic vcpu interface, including the RD device before returning to the caller. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20231207151201.3028710-4-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/arm.c | 2 +- arch/arm64/kvm/vgic/vgic-init.c | 5 ++++- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 2 +- arch/arm64/kvm/vgic/vgic.h | 1 + 4 files changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index e5f75f1f1085..4796104c4471 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -410,7 +410,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache); kvm_timer_vcpu_terminate(vcpu); kvm_pmu_vcpu_destroy(vcpu); - + kvm_vgic_vcpu_destroy(vcpu); kvm_arm_vcpu_destroy(vcpu); } diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c index a86f300321a7..e949e1d0fd9f 100644 --- a/arch/arm64/kvm/vgic/vgic-init.c +++ b/arch/arm64/kvm/vgic/vgic-init.c @@ -379,7 +379,10 @@ static void __kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) vgic_flush_pending_lpis(vcpu); INIT_LIST_HEAD(&vgic_cpu->ap_list_head); - vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF; + if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) { + vgic_unregister_redist_iodev(vcpu); + vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF; + } } void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index 89117ba2528a..0f039d46d4fc 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -820,7 +820,7 @@ out_unlock: return ret; } -static void vgic_unregister_redist_iodev(struct kvm_vcpu *vcpu) +void vgic_unregister_redist_iodev(struct kvm_vcpu *vcpu) { struct vgic_io_device *rd_dev = &vcpu->arch.vgic_cpu.rd_iodev; diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h index 0ab09b0d4440..8d134569d0a1 100644 --- a/arch/arm64/kvm/vgic/vgic.h +++ b/arch/arm64/kvm/vgic/vgic.h @@ -241,6 +241,7 @@ int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq); int vgic_v3_save_pending_tables(struct kvm *kvm); int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count); int vgic_register_redist_iodev(struct kvm_vcpu *vcpu); +void vgic_unregister_redist_iodev(struct kvm_vcpu *vcpu); bool vgic_v3_check_base(struct kvm *kvm); void vgic_v3_load(struct kvm_vcpu *vcpu); From 6bef365e310a5cd4b6e95fbb80b44725fce97e37 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 7 Dec 2023 15:12:00 +0000 Subject: [PATCH 4/6] KVM: arm64: vgic: Ensure that slots_lock is held in vgic_register_all_redist_iodevs() Although we implicitly depend on slots_lock being held when registering IO devices with the IO bus infrastructure, we don't enforce this requirement. Make it explicit. Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20231207151201.3028710-5-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index 0f039d46d4fc..a764b0ab8bf9 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -833,6 +833,8 @@ static int vgic_register_all_redist_iodevs(struct kvm *kvm) unsigned long c; int ret = 0; + lockdep_assert_held(&kvm->slots_lock); + kvm_for_each_vcpu(c, vcpu, kvm) { ret = vgic_register_redist_iodev(vcpu); if (ret) From b1a39a718db44ecb18c2a99a11e15f6eedc14c53 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 7 Dec 2023 15:12:01 +0000 Subject: [PATCH 5/6] KVM: Convert comment into an assertion in kvm_io_bus_register_dev() Instead of having a comment indicating the need to hold slots_lock when calling kvm_io_bus_register_dev(), make it explicit with a lockdep assertion. Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20231207151201.3028710-6-maz@kernel.org Signed-off-by: Oliver Upton --- virt/kvm/kvm_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 486800a7024b..278d31ae45d8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -5545,7 +5545,6 @@ int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr, return r < 0 ? r : 0; } -/* Caller must hold slots_lock. */ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len, struct kvm_io_device *dev) { @@ -5553,6 +5552,8 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, struct kvm_io_bus *new_bus, *bus; struct kvm_io_range range; + lockdep_assert_held(&kvm->slots_lock); + bus = kvm_get_bus(kvm, bus_idx); if (!bus) return -ENOMEM; From 0c12e6c8267f831e491ee64ac6f216601cea3eee Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 12 Dec 2023 07:04:32 +0000 Subject: [PATCH 6/6] KVM: selftests: Ensure sysreg-defs.h is generated at the expected path Building the KVM selftests from the main selftests Makefile (as opposed to the kvm subdirectory) doesn't work as OUTPUT is set, forcing the generated header to spill into the selftests directory. Additionally, relative paths do not work when building outside of the srctree, as the canonical selftests path is replaced with 'kselftest' in the output. Work around both of these issues by explicitly overriding OUTPUT on the submake cmdline. Move the whole fragment below the point lib.mk gets included such that $(abs_objdir) is available. Reviewed-by: Cornelia Huck Tested-by: Mark Brown Link: https://lore.kernel.org/r/20231212070431.145544-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- tools/testing/selftests/kvm/Makefile | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 52c59bad7213..5f4f6be7a866 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -17,16 +17,6 @@ else ARCH_DIR := $(ARCH) endif -ifeq ($(ARCH),arm64) -tools_dir := $(top_srcdir)/tools -arm64_tools_dir := $(tools_dir)/arch/arm64/tools/ -GEN_HDRS := $(top_srcdir)/tools/arch/arm64/include/generated/ -CFLAGS += -I$(GEN_HDRS) - -$(GEN_HDRS): $(wildcard $(arm64_tools_dir)/*) - $(MAKE) -C $(arm64_tools_dir) O=$(tools_dir) -endif - LIBKVM += lib/assert.c LIBKVM += lib/elf.c LIBKVM += lib/guest_modes.c @@ -234,6 +224,22 @@ CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \ ifeq ($(ARCH),s390) CFLAGS += -march=z10 endif +ifeq ($(ARCH),arm64) +tools_dir := $(top_srcdir)/tools +arm64_tools_dir := $(tools_dir)/arch/arm64/tools/ + +ifneq ($(abs_objdir),) +arm64_hdr_outdir := $(abs_objdir)/tools/ +else +arm64_hdr_outdir := $(tools_dir)/ +endif + +GEN_HDRS := $(arm64_hdr_outdir)arch/arm64/include/generated/ +CFLAGS += -I$(GEN_HDRS) + +$(GEN_HDRS): $(wildcard $(arm64_tools_dir)/*) + $(MAKE) -C $(arm64_tools_dir) OUTPUT=$(arm64_hdr_outdir) +endif no-pie-option := $(call try-run, echo 'int main(void) { return 0; }' | \ $(CC) -Werror $(CFLAGS) -no-pie -x c - -o "$$TMP", -no-pie)