Re: [PATCH 9/9] KVM: selftests: Add option to run dirty_log_perf_test vCPUs in L2

[Peter Xu <peterx@redhat.com>]

On Fri, Apr 29, 2022 at 06:39:35PM +0000, David Matlack wrote:
> +static void perf_test_l1_guest_code(struct vmx_pages *vmx, uint64_t vcpu_id)
> +{
> +#define L2_GUEST_STACK_SIZE 64
> +	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
> +	unsigned long *rsp;
> +
> +	GUEST_ASSERT(vmx->vmcs_gpa);
> +	GUEST_ASSERT(prepare_for_vmx_operation(vmx));
> +	GUEST_ASSERT(load_vmcs(vmx));
> +	GUEST_ASSERT(ept_1g_pages_supported());
> +
> +	rsp = &l2_guest_stack[L2_GUEST_STACK_SIZE - 1];
> +	*rsp = vcpu_id;
> +	prepare_vmcs(vmx, perf_test_l2_guest_entry, rsp);

Just to purely ask: is this setting the same stack pointer to all the
vcpus?

> +
> +	GUEST_ASSERT(!vmlaunch());
> +	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
> +	GUEST_DONE();
> +}

[...]

> +/* Identity map the entire guest physical address space with 1GiB Pages. */
> +void nested_map_all_1g(struct vmx_pages *vmx, struct kvm_vm *vm)
> +{
> +	__nested_map(vmx, vm, 0, 0, vm->max_gfn << vm->page_shift, PG_LEVEL_1G);
> +}

Could max_gfn be large?  Could it consumes a bunch of pages even if mapping
1G only?

Thanks,

-- 
Peter Xu