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Subject: Re: [PATCH v1 3/4] selftests: kvm: Add ucall tests for LoongArch KVM
To:     Sean Christopherson <seanjc@google.com>
Cc:     Shuah Khan <shuah@kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        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>, maobibo@loongson.cn
References: <20230801020206.1957986-1-zhaotianrui@loongson.cn>
 <20230801020206.1957986-4-zhaotianrui@loongson.cn>
 <ZMqbqwuCdI2XpJ9q@google.com>
From:   zhaotianrui <zhaotianrui@loongson.cn>
Message-ID: <a3800117-ff95-141c-fe94-9d910f4710dc@loongson.cn>
Date:   Thu, 3 Aug 2023 14:42:24 +0800
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?? 2023/8/3 ????2:08, Sean Christopherson д??:
> On Tue, Aug 01, 2023, Tianrui Zhao wrote:
>> Add ucall tests for LoongArch KVM, it means that VM use hypercall
> s/tests/support
Thanks, I will fix this comment.
>
>> to return to userspace and handle the mmio exception.
>>
>> Based-on: <20230720062813.4126751-1-zhaotianrui@loongson.cn>
>> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
>> ---
>>   .../selftests/kvm/lib/loongarch/ucall.c       | 44 +++++++++++++++++++
>>   1 file changed, 44 insertions(+)
>>   create mode 100644 tools/testing/selftests/kvm/lib/loongarch/ucall.c
>>
>> 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 000000000000..b32f7c7f6548
>> --- /dev/null
>> +++ b/tools/testing/selftests/kvm/lib/loongarch/ucall.c
>> @@ -0,0 +1,44 @@
>> +// 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.
>> + */
>> +static 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_do_ucall(vm_vaddr_t uc)
>> +{
>> +
> Extra newline.
Thanks, I will remove this line.

Thanks
Tianrui Zhao
>
>> +	WRITE_ONCE(*ucall_exit_mmio_addr, uc);
>> +}
>> +
>> +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;
>> +}
>> -- 
>> 2.39.1
>>