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Date:   Mon, 20 Jun 2022 09:39:50 +0200
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Subject: Re: [PATCH 1/3] KVM: selftests: Consolidate common code for
 popuplating ucall struct
Content-Language: en-US
To:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Marc Zyngier <maz@kernel.org>,
        Anup Patel <anup@brainfault.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Janosch Frank <frankja@linux.ibm.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc:     James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Atish Patra <atishp@atishpatra.org>,
        David Hildenbrand <david@redhat.com>, kvm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        Colton Lewis <coltonlewis@google.com>,
        Andrew Jones <drjones@redhat.com>
References: <20220618001618.1840806-1-seanjc@google.com>
 <20220618001618.1840806-2-seanjc@google.com>
From:   Christian Borntraeger <borntraeger@linux.ibm.com>
In-Reply-To: <20220618001618.1840806-2-seanjc@google.com>
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Precedence: bulk


Am 18.06.22 um 02:16 schrieb Sean Christopherson:
> 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...)
> 
> No functional change intended.
> 
> Cc: Colton Lewis <coltonlewis@google.com>
> Cc: Andrew Jones <drjones@redhat.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>

seems to work on s390.
Tested-by: Christian Borntraeger <borntraeger@linux.ibm.com>

> ---
>   tools/testing/selftests/kvm/Makefile          |  1 +
>   .../selftests/kvm/include/ucall_common.h      | 23 ++++++++++++++++---
>   .../testing/selftests/kvm/lib/aarch64/ucall.c | 23 ++++---------------
>   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, 61 insertions(+), 75 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 b52c130f7b2f..bc2aee2af66c 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..c6a4fd7fe443 100644
> --- a/tools/testing/selftests/kvm/include/ucall_common.h
> +++ b/tools/testing/selftests/kvm/include/ucall_common.h
> @@ -23,10 +23,27 @@ 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 0b949ee06b5e..2de9fdd34159 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;
> @@ -64,31 +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 = {
> -		.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)
> +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..749ffdf23855
> --- /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 = {
> +		.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);
> +}
> 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 = {};