From: Ricardo Koller <ricarkol@google.com> To: Marc Zyngier <maz@kernel.org> Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, pbonzini@redhat.com, drjones@redhat.com, alexandru.elisei@arm.com, eric.auger@redhat.com Subject: Re: [PATCH v2 4/5] KVM: selftests: Add exception handling support for aarch64 Date: Mon, 3 May 2021 12:12:21 -0700 [thread overview] Message-ID: <YJBLFVoRmsehRJ1N@google.com> (raw) In-Reply-To: <87a6pcumyg.wl-maz@kernel.org> On Mon, May 03, 2021 at 11:32:39AM +0100, Marc Zyngier wrote: > On Sat, 01 May 2021 00:24:06 +0100, > Ricardo Koller <ricarkol@google.com> wrote: > > > > Add the infrastructure needed to enable exception handling in aarch64 > > selftests. The exception handling defaults to an unhandled-exception > > handler which aborts the test, just like x86. These handlers can be > > overridden by calling vm_install_vector_handler(vector) or > > vm_install_exception_handler(vector, ec). The unhandled exception > > reporting from the guest is done using the ucall type introduced in a > > previous commit, UCALL_UNHANDLED. > > > > The exception handling code is heavily inspired on kvm-unit-tests. > > > > Signed-off-by: Ricardo Koller <ricarkol@google.com> > > --- > > tools/testing/selftests/kvm/Makefile | 2 +- > > .../selftests/kvm/include/aarch64/processor.h | 78 +++++++++++ > > .../selftests/kvm/lib/aarch64/handlers.S | 130 ++++++++++++++++++ > > .../selftests/kvm/lib/aarch64/processor.c | 124 +++++++++++++++++ > > 4 files changed, 333 insertions(+), 1 deletion(-) > > create mode 100644 tools/testing/selftests/kvm/lib/aarch64/handlers.S > > > > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile > > index 4e548d7ab0ab..618c5903f478 100644 > > --- a/tools/testing/selftests/kvm/Makefile > > +++ b/tools/testing/selftests/kvm/Makefile > > @@ -35,7 +35,7 @@ endif > > > > LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/sparsebit.c lib/test_util.c lib/guest_modes.c lib/perf_test_util.c > > LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S > > -LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c > > +LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S > > LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_handler.c > > > > TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test > > diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h > > index b7fa0c8551db..40aae31b4afc 100644 > > --- a/tools/testing/selftests/kvm/include/aarch64/processor.h > > +++ b/tools/testing/selftests/kvm/include/aarch64/processor.h > > @@ -8,6 +8,7 @@ > > #define SELFTEST_KVM_PROCESSOR_H > > > > #include "kvm_util.h" > > +#include <linux/stringify.h> > > > > > > #define ARM64_CORE_REG(x) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ > > @@ -18,6 +19,7 @@ > > #define MAIR_EL1 3, 0, 10, 2, 0 > > #define TTBR0_EL1 3, 0, 2, 0, 0 > > #define SCTLR_EL1 3, 0, 1, 0, 0 > > +#define VBAR_EL1 3, 0, 12, 0, 0 > > > > /* > > * Default MAIR > > @@ -56,4 +58,80 @@ void aarch64_vcpu_setup(struct kvm_vm *vm, int vcpuid, struct kvm_vcpu_init *ini > > void aarch64_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, > > struct kvm_vcpu_init *init, void *guest_code); > > > > +struct ex_regs { > > + u64 regs[31]; > > + u64 sp; > > + u64 pc; > > + u64 pstate; > > +}; > > + > > +#define VECTOR_NUM 16 > > + > > +enum { > > + VECTOR_SYNC_CURRENT_SP0, > > + VECTOR_IRQ_CURRENT_SP0, > > + VECTOR_FIQ_CURRENT_SP0, > > + VECTOR_ERROR_CURRENT_SP0, > > + > > + VECTOR_SYNC_CURRENT, > > + VECTOR_IRQ_CURRENT, > > + VECTOR_FIQ_CURRENT, > > + VECTOR_ERROR_CURRENT, > > + > > + VECTOR_SYNC_LOWER_64, > > + VECTOR_IRQ_LOWER_64, > > + VECTOR_FIQ_LOWER_64, > > + VECTOR_ERROR_LOWER_64, > > + > > + VECTOR_SYNC_LOWER_32, > > + VECTOR_IRQ_LOWER_32, > > + VECTOR_FIQ_LOWER_32, > > + VECTOR_ERROR_LOWER_32, > > +}; > > + > > +#define VECTOR_IS_SYNC(v) ((v) == VECTOR_SYNC_CURRENT_SP0 || \ > > + (v) == VECTOR_SYNC_CURRENT || \ > > + (v) == VECTOR_SYNC_LOWER_64 || \ > > + (v) == VECTOR_SYNC_LOWER_32) > > + > > +/* Some common EC (Exception classes) */ > > +#define ESR_EC_ILLEGAL_INS 0x0e > > +#define ESR_EC_SVC64 0x15 > > +#define ESR_EC_IABORT_CURRENT 0x21 > > +#define ESR_EC_DABORT_CURRENT 0x25 > > +#define ESR_EC_SERROR 0x2f > > +#define ESR_EC_HW_BP_CURRENT 0x31 > > +#define ESR_EC_SSTEP_CURRENT 0x33 > > +#define ESR_EC_WP_CURRENT 0x35 > > +#define ESR_EC_BRK_INS 0x3C > > + > > +#define ESR_EC_NUM 64 > > + > > +#define ESR_EC_SHIFT 26 > > +#define ESR_EC_MASK (ESR_EC_NUM - 1) > > + > > +void vm_init_descriptor_tables(struct kvm_vm *vm); > > +void vcpu_init_descriptor_tables(struct kvm_vm *vm, uint32_t vcpuid); > > + > > +typedef void(*handler_fn)(struct ex_regs *); > > +void vm_install_exception_handler(struct kvm_vm *vm, > > + int vector, int ec, handler_fn handler); > > +void vm_install_vector_handler(struct kvm_vm *vm, > > + int vector, handler_fn handler); > > + > > +#define SPSR_D (1 << 9) > > +#define SPSR_SS (1 << 21) > > + > > +#define write_sysreg(reg, val) \ > > +({ \ > > + u64 __val = (u64)(val); \ > > + asm volatile("msr " __stringify(reg) ", %x0" : : "rZ" (__val)); \ > > +}) > > + > > +#define read_sysreg(reg) \ > > +({ u64 val; \ > > + asm volatile("mrs %0, "__stringify(reg) : "=r"(val) : : "memory");\ > > + val; \ > > +}) > > + > > #endif /* SELFTEST_KVM_PROCESSOR_H */ > > diff --git a/tools/testing/selftests/kvm/lib/aarch64/handlers.S b/tools/testing/selftests/kvm/lib/aarch64/handlers.S > > new file mode 100644 > > index 000000000000..8a560021892b > > --- /dev/null > > +++ b/tools/testing/selftests/kvm/lib/aarch64/handlers.S > > @@ -0,0 +1,130 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +.macro save_registers, vector > > + add sp, sp, #-16 * 17 > > + > > + stp x0, x1, [sp, #16 * 0] > > + stp x2, x3, [sp, #16 * 1] > > + stp x4, x5, [sp, #16 * 2] > > + stp x6, x7, [sp, #16 * 3] > > + stp x8, x9, [sp, #16 * 4] > > + stp x10, x11, [sp, #16 * 5] > > + stp x12, x13, [sp, #16 * 6] > > + stp x14, x15, [sp, #16 * 7] > > + stp x16, x17, [sp, #16 * 8] > > + stp x18, x19, [sp, #16 * 9] > > + stp x20, x21, [sp, #16 * 10] > > + stp x22, x23, [sp, #16 * 11] > > + stp x24, x25, [sp, #16 * 12] > > + stp x26, x27, [sp, #16 * 13] > > + stp x28, x29, [sp, #16 * 14] > > + > > + .if \vector >= 8 > > + mrs x1, sp_el0 > > I'm still a bit perplexed by this. SP_EL0 is never changed, since you > always run in handler mode. Therefore, saving/restoring it is only > overhead. If an exception handler wants to introspect it, it is > already available in the relevant system register. > > Or did you have something else in mind for it? > Not really. The reason for saving sp_el0 in there was just for consistency, so that handlers for both el0 and el1 exceptions could get the sp at regs->sp. Restoring sp_el0 might be too much. So, what do you think of this v3: we keep the saving of sp_el0 into regs->sp (to keep things the same between el0 and el1) and delete the restoring of sp_el0? Thanks, Ricardo > > + .else > > + /* > > + * This stores sp_el1 into ex_regs.sp so exception handlers can > > + * "look" at it. It will _not_ be used to restore the sp_el1 on > > + * return from the exception so handlers can not update it. > > + */ > > + mov x1, sp > > + .endif > > + stp x30, x1, [sp, #16 * 15] /* x30, SP */ > > + > > + mrs x1, elr_el1 > > + mrs x2, spsr_el1 > > + stp x1, x2, [sp, #16 * 16] /* PC, PSTATE */ > > +.endm > > + > > +.macro restore_registers, vector > > + ldp x1, x2, [sp, #16 * 16] /* PC, PSTATE */ > > + msr elr_el1, x1 > > + msr spsr_el1, x2 > > + > > + ldp x30, x1, [sp, #16 * 15] /* x30, SP */ > > + .if \vector >= 8 > > + msr sp_el0, x1 > > + .endif > > + > > + ldp x28, x29, [sp, #16 * 14] > > + ldp x26, x27, [sp, #16 * 13] > > + ldp x24, x25, [sp, #16 * 12] > > + ldp x22, x23, [sp, #16 * 11] > > + ldp x20, x21, [sp, #16 * 10] > > + ldp x18, x19, [sp, #16 * 9] > > + ldp x16, x17, [sp, #16 * 8] > > + ldp x14, x15, [sp, #16 * 7] > > + ldp x12, x13, [sp, #16 * 6] > > + ldp x10, x11, [sp, #16 * 5] > > + ldp x8, x9, [sp, #16 * 4] > > + ldp x6, x7, [sp, #16 * 3] > > + ldp x4, x5, [sp, #16 * 2] > > + ldp x2, x3, [sp, #16 * 1] > > + ldp x0, x1, [sp, #16 * 0] > > + > > + add sp, sp, #16 * 17 > > + > > + eret > > +.endm > > + > > +.pushsection ".entry.text", "ax" > > +.balign 0x800 > > +.global vectors > > +vectors: > > +.popsection > > + > > +.set vector, 0 > > + > > +/* > > + * Build an exception handler for vector and append a jump to it into > > + * vectors (while making sure that it's 0x80 aligned). > > + */ > > +.macro HANDLER, label > > +handler_\()\label: > > + save_registers vector > > + mov x0, sp > > + mov x1, #vector > > + bl route_exception > > + restore_registers vector > > + > > +.pushsection ".entry.text", "ax" > > +.balign 0x80 > > + b handler_\()\label > > +.popsection > > + > > +.set vector, vector + 1 > > +.endm > > + > > +.macro HANDLER_INVALID > > +.pushsection ".entry.text", "ax" > > +.balign 0x80 > > +/* This will abort so no need to save and restore registers. */ > > + mov x0, #vector > > + b kvm_exit_unexpected_vector > > +.popsection > > + > > +.set vector, vector + 1 > > +.endm > > + > > +/* > > + * Caution: be sure to not add anything between the declaration of vectors > > + * above and these macro calls that will build the vectors table below it. > > + */ > > + HANDLER_INVALID // Synchronous EL1t > > + HANDLER_INVALID // IRQ EL1t > > + HANDLER_INVALID // FIQ EL1t > > + HANDLER_INVALID // Error EL1t > > + > > + HANDLER el1h_sync // Synchronous EL1h > > + HANDLER el1h_irq // IRQ EL1h > > + HANDLER el1h_fiq // FIQ EL1h > > + HANDLER el1h_error // Error EL1h > > + > > + HANDLER el0_sync_64 // Synchronous 64-bit EL0 > > + HANDLER el0_irq_64 // IRQ 64-bit EL0 > > + HANDLER el0_fiq_64 // FIQ 64-bit EL0 > > + HANDLER el0_error_64 // Error 64-bit EL0 > > + > > + HANDLER el0_sync_32 // Synchronous 32-bit EL0 > > + HANDLER el0_irq_32 // IRQ 32-bit EL0 > > + HANDLER el0_fiq_32 // FIQ 32-bit EL0 > > + HANDLER el0_error_32 // Error 32-bit EL0 > > diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c > > index cee92d477dc0..25be71ec88be 100644 > > --- a/tools/testing/selftests/kvm/lib/aarch64/processor.c > > +++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c > > @@ -6,6 +6,7 @@ > > */ > > > > #include <linux/compiler.h> > > +#include <assert.h> > > > > #include "kvm_util.h" > > #include "../kvm_util_internal.h" > > @@ -14,6 +15,8 @@ > > #define KVM_GUEST_PAGE_TABLE_MIN_PADDR 0x180000 > > #define DEFAULT_ARM64_GUEST_STACK_VADDR_MIN 0xac0000 > > > > +vm_vaddr_t exception_handlers; > > + > > static uint64_t page_align(struct kvm_vm *vm, uint64_t v) > > { > > return (v + vm->page_size) & ~(vm->page_size - 1); > > @@ -334,6 +337,127 @@ void vcpu_args_set(struct kvm_vm *vm, uint32_t vcpuid, unsigned int num, ...) > > va_end(ap); > > } > > > > +void kvm_exit_unexpected_vector(int vector) > > +{ > > + ucall(UCALL_UNHANDLED, 3, vector, 0, false /* !valid_ec */); > > +} > > + > > +void kvm_exit_unexpected_exception(int vector, uint64_t ec) > > +{ > > + ucall(UCALL_UNHANDLED, 3, vector, ec, true /* valid_ec */); > > +} > > + > > void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid) > > { > > + struct ucall uc; > > + > > + if (get_ucall(vm, vcpuid, &uc) != UCALL_UNHANDLED) > > + return; > > + > > + if (uc.args[2]) /* valid_ec */ { > > + assert(VECTOR_IS_SYNC(uc.args[0])); > > + TEST_ASSERT(false, > > + "Unexpected exception (vector:0x%lx, ec:0x%lx)", > > + uc.args[0], uc.args[1]); > > + } else { > > + assert(!VECTOR_IS_SYNC(uc.args[0])); > > + TEST_ASSERT(false, > > + "Unexpected exception (vector:0x%lx)", > > + uc.args[0]); > > + } > > +} > > + > > +/* > > + * This exception handling code was heavily inspired on kvm-unit-tests. There > > + * is a set of default vector handlers stored in vector_handlers. These default > > + * vector handlers call user-installed handlers stored in exception_handlers. > > + * Synchronous handlers are indexed by (vector, ec), and irq handlers by > > + * (vector, ec=0). > > + */ > > + > > +typedef void(*vector_fn)(struct ex_regs *, int vector); > > + > > +struct handlers { > > + vector_fn vector_handlers[VECTOR_NUM]; > > + handler_fn exception_handlers[VECTOR_NUM][ESR_EC_NUM]; > > +}; > > + > > +void vcpu_init_descriptor_tables(struct kvm_vm *vm, uint32_t vcpuid) > > +{ > > + extern char vectors; > > + > > + set_reg(vm, vcpuid, ARM64_SYS_REG(VBAR_EL1), (uint64_t)&vectors); > > +} > > + > > +void default_sync_handler(struct ex_regs *regs, int vector) > > +{ > > + struct handlers *handlers = (struct handlers *)exception_handlers; > > + uint64_t esr = read_sysreg(esr_el1); > > + uint64_t ec = (esr >> ESR_EC_SHIFT) & ESR_EC_MASK; > > + > > + GUEST_ASSERT(VECTOR_IS_SYNC(vector)); > > + > > + if (handlers && handlers->exception_handlers[vector][ec]) > > + handlers->exception_handlers[vector][ec](regs); > > + else > > + kvm_exit_unexpected_exception(vector, ec); > > +} > > + > > +void default_irq_handler(struct ex_regs *regs, int vector) > > +{ > > + struct handlers *handlers = (struct handlers *)exception_handlers; > > + > > + GUEST_ASSERT(!VECTOR_IS_SYNC(vector)); > > + > > + if (handlers && handlers->exception_handlers[vector][0]) > > + handlers->exception_handlers[vector][0](regs); > > + else > > + kvm_exit_unexpected_vector(vector); > > +} > > + > > +void route_exception(struct ex_regs *regs, int vector) > > +{ > > + struct handlers *handlers = (struct handlers *)exception_handlers; > > + > > + if (handlers && handlers->vector_handlers[vector]) > > + handlers->vector_handlers[vector](regs, vector); > > + else > > + kvm_exit_unexpected_vector(vector); > > +} > > + > > +void vm_init_descriptor_tables(struct kvm_vm *vm) > > +{ > > + struct handlers *handlers; > > + > > + vm->handlers = vm_vaddr_alloc(vm, sizeof(struct handlers), > > + vm->page_size, 0, 0); > > + > > + handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); > > + handlers->vector_handlers[VECTOR_SYNC_CURRENT] = default_sync_handler; > > + handlers->vector_handlers[VECTOR_IRQ_CURRENT] = default_irq_handler; > > + handlers->vector_handlers[VECTOR_SYNC_LOWER_64] = default_sync_handler; > > + handlers->vector_handlers[VECTOR_IRQ_LOWER_64] = default_irq_handler; > > How about FIQ, Error? Although they are unlikely, they are valid > exceptions. > > > + > > + *(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers; > > +} > > + > > +void vm_install_exception_handler(struct kvm_vm *vm, int vector, int ec, > > + void (*handler)(struct ex_regs *)) > > +{ > > + struct handlers *handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); > > + > > + assert(VECTOR_IS_SYNC(vector)); > > + assert(vector < VECTOR_NUM); > > + assert(ec < ESR_EC_NUM); > > + handlers->exception_handlers[vector][ec] = handler; > > +} > > + > > +void vm_install_vector_handler(struct kvm_vm *vm, int vector, > > + void (*handler)(struct ex_regs *)) > > +{ > > + struct handlers *handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); > > + > > + assert(!VECTOR_IS_SYNC(vector)); > > + assert(vector < VECTOR_NUM); > > + handlers->exception_handlers[vector][0] = handler; > > } > > Thanks, > > M. > > -- > Without deviation from the norm, progress is not possible.
WARNING: multiple messages have this Message-ID (diff)
From: Ricardo Koller <ricarkol@google.com> To: Marc Zyngier <maz@kernel.org> Cc: kvm@vger.kernel.org, pbonzini@redhat.com, kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH v2 4/5] KVM: selftests: Add exception handling support for aarch64 Date: Mon, 3 May 2021 12:12:21 -0700 [thread overview] Message-ID: <YJBLFVoRmsehRJ1N@google.com> (raw) In-Reply-To: <87a6pcumyg.wl-maz@kernel.org> On Mon, May 03, 2021 at 11:32:39AM +0100, Marc Zyngier wrote: > On Sat, 01 May 2021 00:24:06 +0100, > Ricardo Koller <ricarkol@google.com> wrote: > > > > Add the infrastructure needed to enable exception handling in aarch64 > > selftests. The exception handling defaults to an unhandled-exception > > handler which aborts the test, just like x86. These handlers can be > > overridden by calling vm_install_vector_handler(vector) or > > vm_install_exception_handler(vector, ec). The unhandled exception > > reporting from the guest is done using the ucall type introduced in a > > previous commit, UCALL_UNHANDLED. > > > > The exception handling code is heavily inspired on kvm-unit-tests. > > > > Signed-off-by: Ricardo Koller <ricarkol@google.com> > > --- > > tools/testing/selftests/kvm/Makefile | 2 +- > > .../selftests/kvm/include/aarch64/processor.h | 78 +++++++++++ > > .../selftests/kvm/lib/aarch64/handlers.S | 130 ++++++++++++++++++ > > .../selftests/kvm/lib/aarch64/processor.c | 124 +++++++++++++++++ > > 4 files changed, 333 insertions(+), 1 deletion(-) > > create mode 100644 tools/testing/selftests/kvm/lib/aarch64/handlers.S > > > > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile > > index 4e548d7ab0ab..618c5903f478 100644 > > --- a/tools/testing/selftests/kvm/Makefile > > +++ b/tools/testing/selftests/kvm/Makefile > > @@ -35,7 +35,7 @@ endif > > > > LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/sparsebit.c lib/test_util.c lib/guest_modes.c lib/perf_test_util.c > > LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S > > -LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c > > +LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S > > LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_handler.c > > > > TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test > > diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h > > index b7fa0c8551db..40aae31b4afc 100644 > > --- a/tools/testing/selftests/kvm/include/aarch64/processor.h > > +++ b/tools/testing/selftests/kvm/include/aarch64/processor.h > > @@ -8,6 +8,7 @@ > > #define SELFTEST_KVM_PROCESSOR_H > > > > #include "kvm_util.h" > > +#include <linux/stringify.h> > > > > > > #define ARM64_CORE_REG(x) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ > > @@ -18,6 +19,7 @@ > > #define MAIR_EL1 3, 0, 10, 2, 0 > > #define TTBR0_EL1 3, 0, 2, 0, 0 > > #define SCTLR_EL1 3, 0, 1, 0, 0 > > +#define VBAR_EL1 3, 0, 12, 0, 0 > > > > /* > > * Default MAIR > > @@ -56,4 +58,80 @@ void aarch64_vcpu_setup(struct kvm_vm *vm, int vcpuid, struct kvm_vcpu_init *ini > > void aarch64_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, > > struct kvm_vcpu_init *init, void *guest_code); > > > > +struct ex_regs { > > + u64 regs[31]; > > + u64 sp; > > + u64 pc; > > + u64 pstate; > > +}; > > + > > +#define VECTOR_NUM 16 > > + > > +enum { > > + VECTOR_SYNC_CURRENT_SP0, > > + VECTOR_IRQ_CURRENT_SP0, > > + VECTOR_FIQ_CURRENT_SP0, > > + VECTOR_ERROR_CURRENT_SP0, > > + > > + VECTOR_SYNC_CURRENT, > > + VECTOR_IRQ_CURRENT, > > + VECTOR_FIQ_CURRENT, > > + VECTOR_ERROR_CURRENT, > > + > > + VECTOR_SYNC_LOWER_64, > > + VECTOR_IRQ_LOWER_64, > > + VECTOR_FIQ_LOWER_64, > > + VECTOR_ERROR_LOWER_64, > > + > > + VECTOR_SYNC_LOWER_32, > > + VECTOR_IRQ_LOWER_32, > > + VECTOR_FIQ_LOWER_32, > > + VECTOR_ERROR_LOWER_32, > > +}; > > + > > +#define VECTOR_IS_SYNC(v) ((v) == VECTOR_SYNC_CURRENT_SP0 || \ > > + (v) == VECTOR_SYNC_CURRENT || \ > > + (v) == VECTOR_SYNC_LOWER_64 || \ > > + (v) == VECTOR_SYNC_LOWER_32) > > + > > +/* Some common EC (Exception classes) */ > > +#define ESR_EC_ILLEGAL_INS 0x0e > > +#define ESR_EC_SVC64 0x15 > > +#define ESR_EC_IABORT_CURRENT 0x21 > > +#define ESR_EC_DABORT_CURRENT 0x25 > > +#define ESR_EC_SERROR 0x2f > > +#define ESR_EC_HW_BP_CURRENT 0x31 > > +#define ESR_EC_SSTEP_CURRENT 0x33 > > +#define ESR_EC_WP_CURRENT 0x35 > > +#define ESR_EC_BRK_INS 0x3C > > + > > +#define ESR_EC_NUM 64 > > + > > +#define ESR_EC_SHIFT 26 > > +#define ESR_EC_MASK (ESR_EC_NUM - 1) > > + > > +void vm_init_descriptor_tables(struct kvm_vm *vm); > > +void vcpu_init_descriptor_tables(struct kvm_vm *vm, uint32_t vcpuid); > > + > > +typedef void(*handler_fn)(struct ex_regs *); > > +void vm_install_exception_handler(struct kvm_vm *vm, > > + int vector, int ec, handler_fn handler); > > +void vm_install_vector_handler(struct kvm_vm *vm, > > + int vector, handler_fn handler); > > + > > +#define SPSR_D (1 << 9) > > +#define SPSR_SS (1 << 21) > > + > > +#define write_sysreg(reg, val) \ > > +({ \ > > + u64 __val = (u64)(val); \ > > + asm volatile("msr " __stringify(reg) ", %x0" : : "rZ" (__val)); \ > > +}) > > + > > +#define read_sysreg(reg) \ > > +({ u64 val; \ > > + asm volatile("mrs %0, "__stringify(reg) : "=r"(val) : : "memory");\ > > + val; \ > > +}) > > + > > #endif /* SELFTEST_KVM_PROCESSOR_H */ > > diff --git a/tools/testing/selftests/kvm/lib/aarch64/handlers.S b/tools/testing/selftests/kvm/lib/aarch64/handlers.S > > new file mode 100644 > > index 000000000000..8a560021892b > > --- /dev/null > > +++ b/tools/testing/selftests/kvm/lib/aarch64/handlers.S > > @@ -0,0 +1,130 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +.macro save_registers, vector > > + add sp, sp, #-16 * 17 > > + > > + stp x0, x1, [sp, #16 * 0] > > + stp x2, x3, [sp, #16 * 1] > > + stp x4, x5, [sp, #16 * 2] > > + stp x6, x7, [sp, #16 * 3] > > + stp x8, x9, [sp, #16 * 4] > > + stp x10, x11, [sp, #16 * 5] > > + stp x12, x13, [sp, #16 * 6] > > + stp x14, x15, [sp, #16 * 7] > > + stp x16, x17, [sp, #16 * 8] > > + stp x18, x19, [sp, #16 * 9] > > + stp x20, x21, [sp, #16 * 10] > > + stp x22, x23, [sp, #16 * 11] > > + stp x24, x25, [sp, #16 * 12] > > + stp x26, x27, [sp, #16 * 13] > > + stp x28, x29, [sp, #16 * 14] > > + > > + .if \vector >= 8 > > + mrs x1, sp_el0 > > I'm still a bit perplexed by this. SP_EL0 is never changed, since you > always run in handler mode. Therefore, saving/restoring it is only > overhead. If an exception handler wants to introspect it, it is > already available in the relevant system register. > > Or did you have something else in mind for it? > Not really. The reason for saving sp_el0 in there was just for consistency, so that handlers for both el0 and el1 exceptions could get the sp at regs->sp. Restoring sp_el0 might be too much. So, what do you think of this v3: we keep the saving of sp_el0 into regs->sp (to keep things the same between el0 and el1) and delete the restoring of sp_el0? Thanks, Ricardo > > + .else > > + /* > > + * This stores sp_el1 into ex_regs.sp so exception handlers can > > + * "look" at it. It will _not_ be used to restore the sp_el1 on > > + * return from the exception so handlers can not update it. > > + */ > > + mov x1, sp > > + .endif > > + stp x30, x1, [sp, #16 * 15] /* x30, SP */ > > + > > + mrs x1, elr_el1 > > + mrs x2, spsr_el1 > > + stp x1, x2, [sp, #16 * 16] /* PC, PSTATE */ > > +.endm > > + > > +.macro restore_registers, vector > > + ldp x1, x2, [sp, #16 * 16] /* PC, PSTATE */ > > + msr elr_el1, x1 > > + msr spsr_el1, x2 > > + > > + ldp x30, x1, [sp, #16 * 15] /* x30, SP */ > > + .if \vector >= 8 > > + msr sp_el0, x1 > > + .endif > > + > > + ldp x28, x29, [sp, #16 * 14] > > + ldp x26, x27, [sp, #16 * 13] > > + ldp x24, x25, [sp, #16 * 12] > > + ldp x22, x23, [sp, #16 * 11] > > + ldp x20, x21, [sp, #16 * 10] > > + ldp x18, x19, [sp, #16 * 9] > > + ldp x16, x17, [sp, #16 * 8] > > + ldp x14, x15, [sp, #16 * 7] > > + ldp x12, x13, [sp, #16 * 6] > > + ldp x10, x11, [sp, #16 * 5] > > + ldp x8, x9, [sp, #16 * 4] > > + ldp x6, x7, [sp, #16 * 3] > > + ldp x4, x5, [sp, #16 * 2] > > + ldp x2, x3, [sp, #16 * 1] > > + ldp x0, x1, [sp, #16 * 0] > > + > > + add sp, sp, #16 * 17 > > + > > + eret > > +.endm > > + > > +.pushsection ".entry.text", "ax" > > +.balign 0x800 > > +.global vectors > > +vectors: > > +.popsection > > + > > +.set vector, 0 > > + > > +/* > > + * Build an exception handler for vector and append a jump to it into > > + * vectors (while making sure that it's 0x80 aligned). > > + */ > > +.macro HANDLER, label > > +handler_\()\label: > > + save_registers vector > > + mov x0, sp > > + mov x1, #vector > > + bl route_exception > > + restore_registers vector > > + > > +.pushsection ".entry.text", "ax" > > +.balign 0x80 > > + b handler_\()\label > > +.popsection > > + > > +.set vector, vector + 1 > > +.endm > > + > > +.macro HANDLER_INVALID > > +.pushsection ".entry.text", "ax" > > +.balign 0x80 > > +/* This will abort so no need to save and restore registers. */ > > + mov x0, #vector > > + b kvm_exit_unexpected_vector > > +.popsection > > + > > +.set vector, vector + 1 > > +.endm > > + > > +/* > > + * Caution: be sure to not add anything between the declaration of vectors > > + * above and these macro calls that will build the vectors table below it. > > + */ > > + HANDLER_INVALID // Synchronous EL1t > > + HANDLER_INVALID // IRQ EL1t > > + HANDLER_INVALID // FIQ EL1t > > + HANDLER_INVALID // Error EL1t > > + > > + HANDLER el1h_sync // Synchronous EL1h > > + HANDLER el1h_irq // IRQ EL1h > > + HANDLER el1h_fiq // FIQ EL1h > > + HANDLER el1h_error // Error EL1h > > + > > + HANDLER el0_sync_64 // Synchronous 64-bit EL0 > > + HANDLER el0_irq_64 // IRQ 64-bit EL0 > > + HANDLER el0_fiq_64 // FIQ 64-bit EL0 > > + HANDLER el0_error_64 // Error 64-bit EL0 > > + > > + HANDLER el0_sync_32 // Synchronous 32-bit EL0 > > + HANDLER el0_irq_32 // IRQ 32-bit EL0 > > + HANDLER el0_fiq_32 // FIQ 32-bit EL0 > > + HANDLER el0_error_32 // Error 32-bit EL0 > > diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c > > index cee92d477dc0..25be71ec88be 100644 > > --- a/tools/testing/selftests/kvm/lib/aarch64/processor.c > > +++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c > > @@ -6,6 +6,7 @@ > > */ > > > > #include <linux/compiler.h> > > +#include <assert.h> > > > > #include "kvm_util.h" > > #include "../kvm_util_internal.h" > > @@ -14,6 +15,8 @@ > > #define KVM_GUEST_PAGE_TABLE_MIN_PADDR 0x180000 > > #define DEFAULT_ARM64_GUEST_STACK_VADDR_MIN 0xac0000 > > > > +vm_vaddr_t exception_handlers; > > + > > static uint64_t page_align(struct kvm_vm *vm, uint64_t v) > > { > > return (v + vm->page_size) & ~(vm->page_size - 1); > > @@ -334,6 +337,127 @@ void vcpu_args_set(struct kvm_vm *vm, uint32_t vcpuid, unsigned int num, ...) > > va_end(ap); > > } > > > > +void kvm_exit_unexpected_vector(int vector) > > +{ > > + ucall(UCALL_UNHANDLED, 3, vector, 0, false /* !valid_ec */); > > +} > > + > > +void kvm_exit_unexpected_exception(int vector, uint64_t ec) > > +{ > > + ucall(UCALL_UNHANDLED, 3, vector, ec, true /* valid_ec */); > > +} > > + > > void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid) > > { > > + struct ucall uc; > > + > > + if (get_ucall(vm, vcpuid, &uc) != UCALL_UNHANDLED) > > + return; > > + > > + if (uc.args[2]) /* valid_ec */ { > > + assert(VECTOR_IS_SYNC(uc.args[0])); > > + TEST_ASSERT(false, > > + "Unexpected exception (vector:0x%lx, ec:0x%lx)", > > + uc.args[0], uc.args[1]); > > + } else { > > + assert(!VECTOR_IS_SYNC(uc.args[0])); > > + TEST_ASSERT(false, > > + "Unexpected exception (vector:0x%lx)", > > + uc.args[0]); > > + } > > +} > > + > > +/* > > + * This exception handling code was heavily inspired on kvm-unit-tests. There > > + * is a set of default vector handlers stored in vector_handlers. These default > > + * vector handlers call user-installed handlers stored in exception_handlers. > > + * Synchronous handlers are indexed by (vector, ec), and irq handlers by > > + * (vector, ec=0). > > + */ > > + > > +typedef void(*vector_fn)(struct ex_regs *, int vector); > > + > > +struct handlers { > > + vector_fn vector_handlers[VECTOR_NUM]; > > + handler_fn exception_handlers[VECTOR_NUM][ESR_EC_NUM]; > > +}; > > + > > +void vcpu_init_descriptor_tables(struct kvm_vm *vm, uint32_t vcpuid) > > +{ > > + extern char vectors; > > + > > + set_reg(vm, vcpuid, ARM64_SYS_REG(VBAR_EL1), (uint64_t)&vectors); > > +} > > + > > +void default_sync_handler(struct ex_regs *regs, int vector) > > +{ > > + struct handlers *handlers = (struct handlers *)exception_handlers; > > + uint64_t esr = read_sysreg(esr_el1); > > + uint64_t ec = (esr >> ESR_EC_SHIFT) & ESR_EC_MASK; > > + > > + GUEST_ASSERT(VECTOR_IS_SYNC(vector)); > > + > > + if (handlers && handlers->exception_handlers[vector][ec]) > > + handlers->exception_handlers[vector][ec](regs); > > + else > > + kvm_exit_unexpected_exception(vector, ec); > > +} > > + > > +void default_irq_handler(struct ex_regs *regs, int vector) > > +{ > > + struct handlers *handlers = (struct handlers *)exception_handlers; > > + > > + GUEST_ASSERT(!VECTOR_IS_SYNC(vector)); > > + > > + if (handlers && handlers->exception_handlers[vector][0]) > > + handlers->exception_handlers[vector][0](regs); > > + else > > + kvm_exit_unexpected_vector(vector); > > +} > > + > > +void route_exception(struct ex_regs *regs, int vector) > > +{ > > + struct handlers *handlers = (struct handlers *)exception_handlers; > > + > > + if (handlers && handlers->vector_handlers[vector]) > > + handlers->vector_handlers[vector](regs, vector); > > + else > > + kvm_exit_unexpected_vector(vector); > > +} > > + > > +void vm_init_descriptor_tables(struct kvm_vm *vm) > > +{ > > + struct handlers *handlers; > > + > > + vm->handlers = vm_vaddr_alloc(vm, sizeof(struct handlers), > > + vm->page_size, 0, 0); > > + > > + handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); > > + handlers->vector_handlers[VECTOR_SYNC_CURRENT] = default_sync_handler; > > + handlers->vector_handlers[VECTOR_IRQ_CURRENT] = default_irq_handler; > > + handlers->vector_handlers[VECTOR_SYNC_LOWER_64] = default_sync_handler; > > + handlers->vector_handlers[VECTOR_IRQ_LOWER_64] = default_irq_handler; > > How about FIQ, Error? Although they are unlikely, they are valid > exceptions. > > > + > > + *(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers; > > +} > > + > > +void vm_install_exception_handler(struct kvm_vm *vm, int vector, int ec, > > + void (*handler)(struct ex_regs *)) > > +{ > > + struct handlers *handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); > > + > > + assert(VECTOR_IS_SYNC(vector)); > > + assert(vector < VECTOR_NUM); > > + assert(ec < ESR_EC_NUM); > > + handlers->exception_handlers[vector][ec] = handler; > > +} > > + > > +void vm_install_vector_handler(struct kvm_vm *vm, int vector, > > + void (*handler)(struct ex_regs *)) > > +{ > > + struct handlers *handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); > > + > > + assert(!VECTOR_IS_SYNC(vector)); > > + assert(vector < VECTOR_NUM); > > + handlers->exception_handlers[vector][0] = handler; > > } > > Thanks, > > M. > > -- > Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
next prev parent reply other threads:[~2021-05-03 19:12 UTC|newest] Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-30 23:24 [PATCH v2 0/5] KVM: selftests: arm64 exception handling and debug test Ricardo Koller 2021-04-30 23:24 ` Ricardo Koller 2021-04-30 23:24 ` [PATCH v2 1/5] KVM: selftests: Rename vm_handle_exception Ricardo Koller 2021-04-30 23:24 ` Ricardo Koller 2021-05-03 11:02 ` Andrew Jones 2021-05-03 11:02 ` Andrew Jones 2021-05-06 12:27 ` Auger Eric 2021-05-06 12:27 ` Auger Eric 2021-04-30 23:24 ` [PATCH v2 2/5] KVM: selftests: Introduce UCALL_UNHANDLED for unhandled vector reporting Ricardo Koller 2021-04-30 23:24 ` Ricardo Koller 2021-05-03 11:09 ` Andrew Jones 2021-05-03 11:09 ` Andrew Jones 2021-05-06 12:27 ` Auger Eric 2021-05-06 12:27 ` Auger Eric 2021-04-30 23:24 ` [PATCH v2 3/5] KVM: selftests: Move GUEST_ASSERT_EQ to utils header Ricardo Koller 2021-04-30 23:24 ` Ricardo Koller 2021-05-03 11:31 ` Andrew Jones 2021-05-03 11:31 ` Andrew Jones 2021-04-30 23:24 ` [PATCH v2 4/5] KVM: selftests: Add exception handling support for aarch64 Ricardo Koller 2021-04-30 23:24 ` Ricardo Koller 2021-05-03 10:32 ` Marc Zyngier 2021-05-03 10:32 ` Marc Zyngier 2021-05-03 19:12 ` Ricardo Koller [this message] 2021-05-03 19:12 ` Ricardo Koller 2021-05-06 12:30 ` Auger Eric 2021-05-06 12:30 ` Auger Eric 2021-05-06 19:14 ` Ricardo Koller 2021-05-06 19:14 ` Ricardo Koller 2021-05-07 14:08 ` Auger Eric 2021-05-07 14:08 ` Auger Eric 2021-05-07 17:54 ` Ricardo Koller 2021-05-07 17:54 ` Ricardo Koller 2021-05-12 7:27 ` Ricardo Koller 2021-05-12 7:27 ` Ricardo Koller 2021-05-12 8:19 ` Auger Eric 2021-05-12 8:19 ` Auger Eric 2021-05-12 8:33 ` Marc Zyngier 2021-05-12 8:33 ` Marc Zyngier 2021-05-12 8:52 ` Auger Eric 2021-05-12 8:52 ` Auger Eric 2021-05-12 16:06 ` Ricardo Koller 2021-05-12 16:06 ` Ricardo Koller 2021-05-12 12:59 ` Zenghui Yu 2021-05-12 12:59 ` Zenghui Yu 2021-05-12 13:43 ` Marc Zyngier 2021-05-12 13:43 ` Marc Zyngier 2021-05-12 16:03 ` Ricardo Koller 2021-05-12 16:03 ` Ricardo Koller 2021-05-12 16:18 ` Marc Zyngier 2021-05-12 16:18 ` Marc Zyngier 2021-05-12 21:39 ` Ricardo Koller 2021-05-12 21:39 ` Ricardo Koller 2021-05-07 14:31 ` Marc Zyngier 2021-05-07 14:31 ` Marc Zyngier 2021-05-07 18:02 ` Ricardo Koller 2021-05-07 18:02 ` Ricardo Koller 2021-05-03 12:39 ` Andrew Jones 2021-05-03 12:39 ` Andrew Jones 2021-04-30 23:24 ` [PATCH v2 5/5] KVM: selftests: Add aarch64/debug-exceptions test Ricardo Koller 2021-04-30 23:24 ` Ricardo Koller 2021-05-03 12:49 ` Andrew Jones 2021-05-03 12:49 ` Andrew Jones 2021-05-24 12:14 ` [PATCH v2 0/5] KVM: selftests: arm64 exception handling and debug test Paolo Bonzini 2021-05-24 12:14 ` Paolo Bonzini 2021-05-24 12:59 ` Marc Zyngier 2021-05-24 12:59 ` Marc Zyngier
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