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Subject: Re: [PATCH v5 3/4] KVM: selftests: Add ucall test support for
 LoongArch
To:     Tianrui Zhao <zhaotianrui@loongson.cn>,
        Shuah Khan <shuah@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        Sean Christopherson <seanjc@google.com>
Cc:     Vishal Annapurve <vannapurve@google.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>, loongarch@lists.linux.dev,
        Peter Xu <peterx@redhat.com>, Vipin Sharma <vipinsh@google.com>
References: <20231130111804.2227570-1-zhaotianrui@loongson.cn>
 <20231130111804.2227570-4-zhaotianrui@loongson.cn>
From:   maobibo <maobibo@loongson.cn>
Message-ID: <de23c3f6-556a-1ddb-bd1e-01bf249cfceb@loongson.cn>
Date:   Mon, 4 Dec 2023 10:05:45 +0800
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On 2023/11/30 下午7:18, Tianrui Zhao wrote:
> Add ucall test support for LoongArch. A ucall is a "hypercall to
> userspace".
> 
> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
> ---
>   .../selftests/kvm/include/loongarch/ucall.h   | 28 ++++++++++++++
>   .../selftests/kvm/lib/loongarch/ucall.c       | 38 +++++++++++++++++++
>   2 files changed, 66 insertions(+)
>   create mode 100644 tools/testing/selftests/kvm/include/loongarch/ucall.h
>   create mode 100644 tools/testing/selftests/kvm/lib/loongarch/ucall.c
> 
> diff --git a/tools/testing/selftests/kvm/include/loongarch/ucall.h b/tools/testing/selftests/kvm/include/loongarch/ucall.h
> new file mode 100644
> index 00000000000..e9033ea6fbf
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/include/loongarch/ucall.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#ifndef SELFTEST_KVM_UCALL_H
> +#define SELFTEST_KVM_UCALL_H
> +
> +#include "kvm_util_base.h"
> +
> +#define UCALL_EXIT_REASON       KVM_EXIT_MMIO
> +
> +/*
> + * Default base address for application loading is 0x120000000,
> + * DEFAULT_GUEST_TEST_MEM should be larger than app loading address,
> + * so that PER_VCPU_MEM_SIZE can be large enough, and kvm selftests
> + * app size is smaller than 256M in generic
> + */
> +#define DEFAULT_GUEST_TEST_MEM	0x130000000
> +
> +/*
> + * ucall_exit_mmio_addr holds per-VM values (global data is duplicated by each
> + * VM), it must not be accessed from host code.
> + */
> +extern vm_vaddr_t *ucall_exit_mmio_addr;
> +
> +static inline void ucall_arch_do_ucall(vm_vaddr_t uc)
> +{
> +	WRITE_ONCE(*ucall_exit_mmio_addr, uc);
> +}
> +
> +#endif
> diff --git a/tools/testing/selftests/kvm/lib/loongarch/ucall.c b/tools/testing/selftests/kvm/lib/loongarch/ucall.c
> new file mode 100644
> index 00000000000..fc6cbb50573
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/loongarch/ucall.c
> @@ -0,0 +1,38 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ucall support. A ucall is a "hypercall to userspace".
> + *
> + */
> +#include "kvm_util.h"
> +
> +/*
> + * ucall_exit_mmio_addr holds per-VM values (global data is duplicated by each
> + * VM), it must not be accessed from host code.
> + */
> +vm_vaddr_t *ucall_exit_mmio_addr;
> +
> +void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
> +{
> +	vm_vaddr_t mmio_gva = vm_vaddr_unused_gap(vm, vm->page_size, KVM_UTIL_MIN_VADDR);
> +
> +	virt_map(vm, mmio_gva, mmio_gpa, 1);
> +
> +	vm->ucall_mmio_addr = mmio_gpa;
> +
> +	write_guest_global(vm, ucall_exit_mmio_addr, (vm_vaddr_t *)mmio_gva);
> +}
> +
> +void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_run *run = vcpu->run;
> +
> +	if (run->exit_reason == KVM_EXIT_MMIO &&
> +	    run->mmio.phys_addr == vcpu->vm->ucall_mmio_addr) {
> +		TEST_ASSERT(run->mmio.is_write && run->mmio.len == sizeof(uint64_t),
> +			    "Unexpected ucall exit mmio address access");
> +
> +		return (void *)(*((uint64_t *)run->mmio.data));
> +	}
> +
> +	return NULL;
> +}
> 
Reviewed-by: Bibo Mao <maobibo@loongson.cn>