Messages in this thread | | | Date | Sun, 19 Jun 2022 18:36:10 +0800 | Subject | Re: [PATCH 2/3] KVM: selftests: Consolidate boilerplate code in get_ucall() | From | "Huang, Shaoqin" <> |
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On 6/18/2022 8:16 AM, Sean Christopherson wrote: > 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).
It seems the get_ucall() returns the uc->cmd, the ucall_arch_get_ucall() returns a host virtual address.
> > Use pointer shenanigans instead of an unnecessary bounce buffer when the > caller of get_ucall() provides a valid pointer. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > .../selftests/kvm/include/ucall_common.h | 8 ++------ > .../testing/selftests/kvm/lib/aarch64/ucall.c | 15 +++------------ > tools/testing/selftests/kvm/lib/riscv/ucall.c | 19 +++---------------- > tools/testing/selftests/kvm/lib/s390x/ucall.c | 16 +++------------- > .../testing/selftests/kvm/lib/ucall_common.c | 19 +++++++++++++++++++ > .../testing/selftests/kvm/lib/x86_64/ucall.c | 16 +++------------- > 6 files changed, 33 insertions(+), 60 deletions(-) > > diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h > index c6a4fd7fe443..cb9b37282701 100644 > --- a/tools/testing/selftests/kvm/include/ucall_common.h > +++ b/tools/testing/selftests/kvm/include/ucall_common.h > @@ -26,9 +26,10 @@ struct ucall { > 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); > -uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *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) > { > @@ -40,11 +41,6 @@ static inline void ucall_uninit(struct kvm_vm *vm) > ucall_arch_uninit(vm); > } > > -static inline uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc) > -{ > - return ucall_arch_get_ucall(vcpu, uc); > -} > - > #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 2de9fdd34159..9c124adbb560 100644 > --- a/tools/testing/selftests/kvm/lib/aarch64/ucall.c > +++ b/tools/testing/selftests/kvm/lib/aarch64/ucall.c > @@ -75,13 +75,9 @@ void ucall_arch_do_ucall(vm_vaddr_t uc) > *ucall_exit_mmio_addr = uc; > } > > -uint64_t ucall_arch_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) { > @@ -90,12 +86,7 @@ uint64_t ucall_arch_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/riscv/ucall.c b/tools/testing/selftests/kvm/lib/riscv/ucall.c > index b1598f418c1f..37e091d4366e 100644 > --- a/tools/testing/selftests/kvm/lib/riscv/ucall.c > +++ b/tools/testing/selftests/kvm/lib/riscv/ucall.c > @@ -51,27 +51,15 @@ void ucall_arch_do_ucall(vm_vaddr_t uc) > uc, 0, 0, 0, 0, 0); > } > > -uint64_t ucall_arch_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"); > @@ -80,6 +68,5 @@ uint64_t ucall_arch_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 114cb4af295f..0f695a031d35 100644 > --- a/tools/testing/selftests/kvm/lib/s390x/ucall.c > +++ b/tools/testing/selftests/kvm/lib/s390x/ucall.c > @@ -20,13 +20,9 @@ void ucall_arch_do_ucall(vm_vaddr_t uc) > asm volatile ("diag 0,%0,0x501" : : "a"(uc) : "memory"); > } > > -uint64_t ucall_arch_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 && > @@ -34,13 +30,7 @@ uint64_t ucall_arch_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 > index 749ffdf23855..c488ed23d0dd 100644 > --- a/tools/testing/selftests/kvm/lib/ucall_common.c > +++ b/tools/testing/selftests/kvm/lib/ucall_common.c > @@ -18,3 +18,22 @@ void ucall(uint64_t cmd, int nargs, ...) > > 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 9f532dba1003..ec53a406f689 100644 > --- a/tools/testing/selftests/kvm/lib/x86_64/ucall.c > +++ b/tools/testing/selftests/kvm/lib/x86_64/ucall.c > @@ -22,25 +22,15 @@ void ucall_arch_do_ucall(vm_vaddr_t uc) > : : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory"); > } > > -uint64_t ucall_arch_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; > }
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