From 57e5c1fef5ecc7c346ff971817ba6985643e0a24 Mon Sep 17 00:00:00 2001 From: Aaron Lewis Date: Fri, 28 Jul 2023 17:36:16 -0700 Subject: [PATCH] KVM: selftests: Add string formatting options to ucall Add more flexibility to guest debugging and testing by adding GUEST_PRINTF() and GUEST_ASSERT_FMT() to the ucall framework. Add a sized buffer to the ucall structure to hold the formatted string, i.e. to allow the guest to easily resolve the string, and thus avoid the ugly pattern of the host side having to make assumptions about the desired format, as well as having to pass around a large number of parameters. The buffer size was chosen to accommodate most use cases, and based on similar usage. E.g. printf() uses the same size buffer in arch/x86/boot/printf.c. And 1KiB ought to be enough for anybody. Signed-off-by: Aaron Lewis [sean: massage changelog, wrap macro param in ()] Link: https://lore.kernel.org/r/20230729003643.1053367-8-seanjc@google.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/include/ucall_common.h | 7 +++++++ tools/testing/selftests/kvm/lib/ucall_common.c | 17 +++++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h index bcbb362..b5548ae 100644 --- a/tools/testing/selftests/kvm/include/ucall_common.h +++ b/tools/testing/selftests/kvm/include/ucall_common.h @@ -13,15 +13,18 @@ enum { UCALL_NONE, UCALL_SYNC, UCALL_ABORT, + UCALL_PRINTF, UCALL_DONE, UCALL_UNHANDLED, }; #define UCALL_MAX_ARGS 7 +#define UCALL_BUFFER_LEN 1024 struct ucall { uint64_t cmd; uint64_t args[UCALL_MAX_ARGS]; + char buffer[UCALL_BUFFER_LEN]; /* Host virtual address of this struct. */ struct ucall *hva; @@ -32,6 +35,7 @@ void ucall_arch_do_ucall(vm_vaddr_t uc); void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu); void ucall(uint64_t cmd, int nargs, ...); +void ucall_fmt(uint64_t cmd, const char *fmt, ...); uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc); void ucall_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa); int ucall_nr_pages_required(uint64_t page_size); @@ -47,8 +51,11 @@ int ucall_nr_pages_required(uint64_t page_size); #define GUEST_SYNC_ARGS(stage, arg1, arg2, arg3, arg4) \ ucall(UCALL_SYNC, 6, "hello", stage, arg1, arg2, arg3, arg4) #define GUEST_SYNC(stage) ucall(UCALL_SYNC, 2, "hello", stage) +#define GUEST_PRINTF(_fmt, _args...) ucall_fmt(UCALL_PRINTF, _fmt, ##_args) #define GUEST_DONE() ucall(UCALL_DONE, 0) +#define REPORT_GUEST_PRINTF(ucall) pr_info("%s", (ucall).buffer) + enum guest_assert_builtin_args { GUEST_ERROR_STRING, GUEST_FILE, diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c index 77ada36..b507db9 100644 --- a/tools/testing/selftests/kvm/lib/ucall_common.c +++ b/tools/testing/selftests/kvm/lib/ucall_common.c @@ -75,6 +75,23 @@ static void ucall_free(struct ucall *uc) clear_bit(uc - ucall_pool->ucalls, ucall_pool->in_use); } +void ucall_fmt(uint64_t cmd, const char *fmt, ...) +{ + struct ucall *uc; + va_list va; + + uc = ucall_alloc(); + uc->cmd = cmd; + + va_start(va, fmt); + guest_vsnprintf(uc->buffer, UCALL_BUFFER_LEN, fmt, va); + va_end(va); + + ucall_arch_do_ucall((vm_vaddr_t)uc->hva); + + ucall_free(uc); +} + void ucall(uint64_t cmd, int nargs, ...) { struct ucall *uc; -- 2.7.4