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From: Andrew Jones To: Peter Gonda Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, marcorr@google.com, seanjc@google.com, michael.roth@amd.com, thomas.lendacky@amd.com, joro@8bytes.org, mizhang@google.com, pbonzini@redhat.com Subject: Re: [RFC V1 06/10] KVM: selftests: Consolidate boilerplate code in get_ucall() Message-ID: <20220719144228.txirbh36ezv6fgrj@kamzik> References: <20220715192956.1873315-1-pgonda@google.com> <20220715192956.1873315-8-pgonda@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220715192956.1873315-8-pgonda@google.com> X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 15, 2022 at 12:29:52PM -0700, Peter Gonda wrote: > From: Sean Christopherson > > Consolidate the actual copying of a ucall struct from guest=>host into > the common get_ucall(). Return a host virtual address instead of a guest > virtual address even though the addr_gva2hva() part could be moved to > get_ucall() too. Conceptually, get_ucall() is invoked from the host and > should return a host virtual address (and returning NULL for "nothing to > see here" is far superior to returning 0). > > Use pointer shenanigans instead of an unnecessary bounce buffer when the > caller of get_ucall() provides a valid pointer. > > Signed-off-by: Sean Christopherson > Signed-off-by: Peter Gonda > > --- > tools/testing/selftests/kvm/Makefile | 1 + > .../selftests/kvm/include/ucall_common.h | 17 +++++++- > .../testing/selftests/kvm/lib/aarch64/ucall.c | 36 ++++------------- > .../selftests/kvm/lib/perf_test_util.c | 2 +- > tools/testing/selftests/kvm/lib/riscv/ucall.c | 40 ++++--------------- > tools/testing/selftests/kvm/lib/s390x/ucall.c | 37 ++++------------- > .../testing/selftests/kvm/lib/ucall_common.c | 39 ++++++++++++++++++ > .../testing/selftests/kvm/lib/x86_64/ucall.c | 37 ++++------------- > 8 files changed, 84 insertions(+), 125 deletions(-) > create mode 100644 tools/testing/selftests/kvm/lib/ucall_common.c > > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile > index 4d6753aadfa0..61e85892dd9b 100644 > --- a/tools/testing/selftests/kvm/Makefile > +++ b/tools/testing/selftests/kvm/Makefile > @@ -46,6 +46,7 @@ LIBKVM += lib/perf_test_util.c > LIBKVM += lib/rbtree.c > LIBKVM += lib/sparsebit.c > LIBKVM += lib/test_util.c > +LIBKVM += lib/ucall_common.c > > LIBKVM_x86_64 += lib/x86_64/apic.c > LIBKVM_x86_64 += lib/x86_64/handlers.S > diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h > index 98562f685151..cb9b37282701 100644 > --- a/tools/testing/selftests/kvm/include/ucall_common.h > +++ b/tools/testing/selftests/kvm/include/ucall_common.h > @@ -23,11 +23,24 @@ struct ucall { > uint64_t args[UCALL_MAX_ARGS]; > }; > > -void ucall_init(struct kvm_vm *vm, void *arg); > -void ucall_uninit(struct kvm_vm *vm); > +void ucall_arch_init(struct kvm_vm *vm, void *arg); > +void ucall_arch_uninit(struct kvm_vm *vm); > +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, ...); > uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc); > > +static inline void ucall_init(struct kvm_vm *vm, void *arg) > +{ > + ucall_arch_init(vm, arg); > +} > + > +static inline void ucall_uninit(struct kvm_vm *vm) > +{ > + ucall_arch_uninit(vm); > +} > + > #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) > diff --git a/tools/testing/selftests/kvm/lib/aarch64/ucall.c b/tools/testing/selftests/kvm/lib/aarch64/ucall.c > index 0b949ee06b5e..9c124adbb560 100644 > --- a/tools/testing/selftests/kvm/lib/aarch64/ucall.c > +++ b/tools/testing/selftests/kvm/lib/aarch64/ucall.c > @@ -21,7 +21,7 @@ static bool ucall_mmio_init(struct kvm_vm *vm, vm_paddr_t gpa) > return true; > } > > -void ucall_init(struct kvm_vm *vm, void *arg) > +void ucall_arch_init(struct kvm_vm *vm, void *arg) > { > vm_paddr_t gpa, start, end, step, offset; > unsigned int bits; > @@ -64,37 +64,20 @@ void ucall_init(struct kvm_vm *vm, void *arg) > TEST_FAIL("Can't find a ucall mmio address"); > } > > -void ucall_uninit(struct kvm_vm *vm) > +void ucall_arch_uninit(struct kvm_vm *vm) > { > ucall_exit_mmio_addr = 0; > sync_global_to_guest(vm, ucall_exit_mmio_addr); > } > > -void ucall(uint64_t cmd, int nargs, ...) > +void ucall_arch_do_ucall(vm_vaddr_t uc) > { > - struct ucall uc = { > - .cmd = cmd, > - }; > - va_list va; > - int i; > - > - nargs = min(nargs, UCALL_MAX_ARGS); > - > - va_start(va, nargs); > - for (i = 0; i < nargs; ++i) > - uc.args[i] = va_arg(va, uint64_t); > - va_end(va); > - > - *ucall_exit_mmio_addr = (vm_vaddr_t)&uc; > + *ucall_exit_mmio_addr = uc; > } > > -uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > +void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu) > { > struct kvm_run *run = vcpu->run; > - struct ucall ucall = {}; > - > - if (uc) > - memset(uc, 0, sizeof(*uc)); > > if (run->exit_reason == KVM_EXIT_MMIO && > run->mmio.phys_addr == (uint64_t)ucall_exit_mmio_addr) { > @@ -103,12 +86,7 @@ uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > TEST_ASSERT(run->mmio.is_write && run->mmio.len == 8, > "Unexpected ucall exit mmio address access"); > memcpy(&gva, run->mmio.data, sizeof(gva)); > - memcpy(&ucall, addr_gva2hva(vcpu->vm, gva), sizeof(ucall)); > - > - vcpu_run_complete_io(vcpu); > - if (uc) > - memcpy(uc, &ucall, sizeof(ucall)); > + return addr_gva2hva(vcpu->vm, gva); > } > - > - return ucall.cmd; > + return NULL; > } > diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c > index 9618b37c66f7..14f88f3ffa80 100644 > --- a/tools/testing/selftests/kvm/lib/perf_test_util.c > +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c > @@ -209,7 +209,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int nr_vcpus, > perf_test_setup_nested(vm, nr_vcpus, vcpus); > } > > - ucall_init(vm, NULL); > + ucall_arch_init(vm, NULL); This change shouldn't be necessary since we have the ucall_init() wrapper in ucall_common.h > > /* Export the shared variables to the guest. */ > sync_global_to_guest(vm, perf_test_args); > diff --git a/tools/testing/selftests/kvm/lib/riscv/ucall.c b/tools/testing/selftests/kvm/lib/riscv/ucall.c > index 087b9740bc8f..37e091d4366e 100644 > --- a/tools/testing/selftests/kvm/lib/riscv/ucall.c > +++ b/tools/testing/selftests/kvm/lib/riscv/ucall.c > @@ -10,11 +10,11 @@ > #include "kvm_util.h" > #include "processor.h" > > -void ucall_init(struct kvm_vm *vm, void *arg) > +void ucall_arch_init(struct kvm_vm *vm, void *arg) > { > } > > -void ucall_uninit(struct kvm_vm *vm) > +void ucall_arch_uninit(struct kvm_vm *vm) > { > } > > @@ -44,47 +44,22 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0, > return ret; > } > > -void ucall(uint64_t cmd, int nargs, ...) > +void ucall_arch_do_ucall(vm_vaddr_t uc) > { > - struct ucall uc = { > - .cmd = cmd, > - }; > - va_list va; > - int i; > - > - nargs = min(nargs, UCALL_MAX_ARGS); > - > - va_start(va, nargs); > - for (i = 0; i < nargs; ++i) > - uc.args[i] = va_arg(va, uint64_t); > - va_end(va); > - > sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT, > KVM_RISCV_SELFTESTS_SBI_UCALL, > - (vm_vaddr_t)&uc, 0, 0, 0, 0, 0); > + uc, 0, 0, 0, 0, 0); > } > > -uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > +void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu) > { > struct kvm_run *run = vcpu->run; > - struct ucall ucall = {}; > - > - if (uc) > - memset(uc, 0, sizeof(*uc)); > > if (run->exit_reason == KVM_EXIT_RISCV_SBI && > run->riscv_sbi.extension_id == KVM_RISCV_SELFTESTS_SBI_EXT) { > switch (run->riscv_sbi.function_id) { > case KVM_RISCV_SELFTESTS_SBI_UCALL: > - memcpy(&ucall, > - addr_gva2hva(vcpu->vm, run->riscv_sbi.args[0]), > - sizeof(ucall)); > - > - vcpu_run_complete_io(vcpu); > - if (uc) > - memcpy(uc, &ucall, sizeof(ucall)); > - > - break; > + return addr_gva2hva(vcpu->vm, run->riscv_sbi.args[0]); > case KVM_RISCV_SELFTESTS_SBI_UNEXP: > vcpu_dump(stderr, vcpu, 2); > TEST_ASSERT(0, "Unexpected trap taken by guest"); > @@ -93,6 +68,5 @@ uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > break; > } > } > - > - return ucall.cmd; > + return NULL; > } > diff --git a/tools/testing/selftests/kvm/lib/s390x/ucall.c b/tools/testing/selftests/kvm/lib/s390x/ucall.c > index 73dc4e21190f..0f695a031d35 100644 > --- a/tools/testing/selftests/kvm/lib/s390x/ucall.c > +++ b/tools/testing/selftests/kvm/lib/s390x/ucall.c > @@ -6,40 +6,23 @@ > */ > #include "kvm_util.h" > > -void ucall_init(struct kvm_vm *vm, void *arg) > +void ucall_arch_init(struct kvm_vm *vm, void *arg) > { > } > > -void ucall_uninit(struct kvm_vm *vm) > +void ucall_arch_uninit(struct kvm_vm *vm) > { > } > > -void ucall(uint64_t cmd, int nargs, ...) > +void ucall_arch_do_ucall(vm_vaddr_t uc) > { > - struct ucall uc = { > - .cmd = cmd, > - }; > - va_list va; > - int i; > - > - nargs = min(nargs, UCALL_MAX_ARGS); > - > - va_start(va, nargs); > - for (i = 0; i < nargs; ++i) > - uc.args[i] = va_arg(va, uint64_t); > - va_end(va); > - > /* Exit via DIAGNOSE 0x501 (normally used for breakpoints) */ > - asm volatile ("diag 0,%0,0x501" : : "a"(&uc) : "memory"); > + asm volatile ("diag 0,%0,0x501" : : "a"(uc) : "memory"); > } > > -uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > +void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu) > { > struct kvm_run *run = vcpu->run; > - struct ucall ucall = {}; > - > - if (uc) > - memset(uc, 0, sizeof(*uc)); > > if (run->exit_reason == KVM_EXIT_S390_SIEIC && > run->s390_sieic.icptcode == 4 && > @@ -47,13 +30,7 @@ uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > (run->s390_sieic.ipb >> 16) == 0x501) { > int reg = run->s390_sieic.ipa & 0xf; > > - memcpy(&ucall, addr_gva2hva(vcpu->vm, run->s.regs.gprs[reg]), > - sizeof(ucall)); > - > - vcpu_run_complete_io(vcpu); > - if (uc) > - memcpy(uc, &ucall, sizeof(ucall)); > + return addr_gva2hva(vcpu->vm, run->s.regs.gprs[reg]); > } > - > - return ucall.cmd; > + return NULL; > } > diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c > new file mode 100644 > index 000000000000..c488ed23d0dd > --- /dev/null > +++ b/tools/testing/selftests/kvm/lib/ucall_common.c > @@ -0,0 +1,39 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +#include "kvm_util.h" > + > +void ucall(uint64_t cmd, int nargs, ...) > +{ > + struct ucall uc = { > + .cmd = cmd, > + }; > + va_list va; > + int i; > + > + nargs = min(nargs, UCALL_MAX_ARGS); > + > + va_start(va, nargs); > + for (i = 0; i < nargs; ++i) > + uc.args[i] = va_arg(va, uint64_t); > + va_end(va); > + > + ucall_arch_do_ucall((vm_vaddr_t)&uc); > +} > + > +uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > +{ > + struct ucall ucall; > + void *addr; > + > + if (!uc) > + uc = &ucall; > + > + addr = ucall_arch_get_ucall(vcpu); > + if (addr) { > + memcpy(uc, addr, sizeof(*uc)); > + vcpu_run_complete_io(vcpu); > + } else { > + memset(uc, 0, sizeof(*uc)); > + } > + > + return uc->cmd; > +} > diff --git a/tools/testing/selftests/kvm/lib/x86_64/ucall.c b/tools/testing/selftests/kvm/lib/x86_64/ucall.c > index e5f0f9e0d3ee..ec53a406f689 100644 > --- a/tools/testing/selftests/kvm/lib/x86_64/ucall.c > +++ b/tools/testing/selftests/kvm/lib/x86_64/ucall.c > @@ -8,52 +8,29 @@ > > #define UCALL_PIO_PORT ((uint16_t)0x1000) > > -void ucall_init(struct kvm_vm *vm, void *arg) > +void ucall_arch_init(struct kvm_vm *vm, void *arg) > { > } > > -void ucall_uninit(struct kvm_vm *vm) > +void ucall_arch_uninit(struct kvm_vm *vm) > { > } > > -void ucall(uint64_t cmd, int nargs, ...) > +void ucall_arch_do_ucall(vm_vaddr_t uc) > { > - struct ucall uc = { > - .cmd = cmd, > - }; > - va_list va; > - int i; > - > - nargs = min(nargs, UCALL_MAX_ARGS); > - > - va_start(va, nargs); > - for (i = 0; i < nargs; ++i) > - uc.args[i] = va_arg(va, uint64_t); > - va_end(va); > - > asm volatile("in %[port], %%al" > - : : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax", "memory"); > + : : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory"); > } > > -uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > +void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu) > { > struct kvm_run *run = vcpu->run; > - struct ucall ucall = {}; > - > - if (uc) > - memset(uc, 0, sizeof(*uc)); > > if (run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) { > struct kvm_regs regs; > > vcpu_regs_get(vcpu, ®s); > - memcpy(&ucall, addr_gva2hva(vcpu->vm, (vm_vaddr_t)regs.rdi), > - sizeof(ucall)); > - > - vcpu_run_complete_io(vcpu); > - if (uc) > - memcpy(uc, &ucall, sizeof(ucall)); > + return addr_gva2hva(vcpu->vm, (vm_vaddr_t)regs.rdi); > } > - > - return ucall.cmd; > + return NULL; > } > -- > 2.37.0.170.g444d1eabd0-goog > Other than the ucall_init() wrapper comment Reviewed-by: Andrew Jones