Re: [PATCH v1 3/4] selftests: kvm: Add ucall tests for LoongArch KVM

[Sean Christopherson]

On Tue, Aug 01, 2023, Tianrui Zhao wrote:
> Add ucall tests for LoongArch KVM, it means that VM use hypercall

s/tests/support

> to return to userspace and handle the mmio exception.
> 
> Based-on: <20230720062813.4126751-1-zhaotianrui@xxxxxxxxxxx>
> Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
> ---
>  .../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.

> +	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
>