Re: [V3 06/11] KVM: selftests: Consolidate common code for popuplating

Andrew Jones
2022-08-16T15:26:44Z

On Wed, Aug 10, 2022 at 08:20:28AM -0700, Peter Gonda wrote:
> From: Sean Christopherson <seanjc@google.com>
>
> Make ucall() a common helper that populates struct ucall, and only calls
> into arch code to make the actually call out to userspace.
>
> Rename all arch-specific helpers to make it clear they're arch-specific,
> and to avoid collisions with common helpers (one more on its way...)
>
> Add WRITE_ONCE() to stores in ucall() code to as already done to aarch64
> code in commit 9e2f6498efbb ("selftests: KVM: Handle compiler
> optimizations in ucall") to prevent clang optimizations breaking ucalls.
>
> Cc: Colton Lewis <coltonlewis@google.com>
> Cc: Andrew Jones <drjones@redhat.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Peter Gonda <pgonda@google.com>
> ---
> tools/testing/selftests/kvm/Makefile | 1 +
> .../selftests/kvm/include/ucall_common.h | 23 ++++++++++++++++---
> .../testing/selftests/kvm/lib/aarch64/ucall.c | 20 ++++------------
> tools/testing/selftests/kvm/lib/riscv/ucall.c | 23 ++++---------------
> tools/testing/selftests/kvm/lib/s390x/ucall.c | 23 ++++---------------
> .../testing/selftests/kvm/lib/ucall_common.c | 20 ++++++++++++++++
> .../testing/selftests/kvm/lib/x86_64/ucall.c | 23 ++++---------------
> 7 files changed, 60 insertions(+), 73 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 690b499c3471..39fc5e8e5594 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 ee79d180e07e..5a85f5318bbe 100644
> --- a/tools/testing/selftests/kvm/include/ucall_common.h
> +++ b/tools/testing/selftests/kvm/include/ucall_common.h
> @@ -24,10 +24,27 @@ 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);
> +uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc);
> +
> 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);
> +}
> +
> +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)
> diff --git a/tools/testing/selftests/kvm/lib/aarch64/ucall.c b/tools/testing/selftests/kvm/lib/aarch64/ucall.c
> index ed237b744690..1c81a6a5c1f2 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;
> @@ -64,30 +64,18 @@ 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 = {};
> - va_list va;
> - int i;
> -
> - WRITE_ONCE(uc.cmd, cmd);
> - nargs = min(nargs, UCALL_MAX_ARGS);
> -
> - va_start(va, nargs);
> - for (i = 0; i < nargs; ++i)
> - WRITE_ONCE(uc.args[i], va_arg(va, uint64_t));
> - va_end(va);
> -
> WRITE_ONCE(*ucall_exit_mmio_addr, (vm_vaddr_t)&uc);
^ should just be uc

> }
>
> -uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
> +uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
> {
> struct kvm_run *run = vcpu->run;
> struct ucall ucall = {};
> diff --git a/tools/testing/selftests/kvm/lib/riscv/ucall.c b/tools/testing/selftests/kvm/lib/riscv/ucall.c
> index 087b9740bc8f..b1598f418c1f 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)
> {
> }
>
> @@ -44,27 +44,14 @@ 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)
> +uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
> {
> struct kvm_run *run = vcpu->run;
> struct ucall ucall = {};
> diff --git a/tools/testing/selftests/kvm/lib/s390x/ucall.c b/tools/testing/selftests/kvm/lib/s390x/ucall.c
> index 73dc4e21190f..114cb4af295f 100644
> --- a/tools/testing/selftests/kvm/lib/s390x/ucall.c
> +++ b/tools/testing/selftests/kvm/lib/s390x/ucall.c
> @@ -6,34 +6,21 @@
> */
> #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)
> +uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
> {
> struct kvm_run *run = vcpu->run;
> struct ucall ucall = {};
> 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..2395c7f1d543
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/ucall_common.c
> @@ -0,0 +1,20 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include "kvm_util.h"
> +
> +void ucall(uint64_t cmd, int nargs, ...)
> +{
> + struct ucall uc = {};
> + va_list va;
> + int i;
> +
> + WRITE_ONCE(uc.cmd, cmd);
> +
> + nargs = min(nargs, UCALL_MAX_ARGS);
> +
> + va_start(va, nargs);
> + for (i = 0; i < nargs; ++i)
> + WRITE_ONCE(uc.args[i], va_arg(va, uint64_t));
> + va_end(va);
> +
> + ucall_arch_do_ucall((vm_vaddr_t)&uc);
> +}
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/ucall.c b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
> index e5f0f9e0d3ee..9f532dba1003 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/ucall.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
> @@ -8,34 +8,21 @@
>
> #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)
> +uint64_t ucall_arch_get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
> {
> struct kvm_run *run = vcpu->run;
> struct ucall ucall = {};
> --
> 2.37.1.559.g78731f0fdb-goog
>

Otherwise,

Reviewed-by: Andrew Jones <andrew.jones@linux.dev>