From 6e1d13bf3815d6058620dd72135be292d9f44bc9 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 3 May 2022 09:52:48 -0700 Subject: KVM: selftests: Move per-VM/per-vCPU nr pages calculation to __vm_create() Handle all memslot0 size adjustments in __vm_create(). Currently, the adjustments reside in __vm_create_with_vcpus(), which means tests that call vm_create() or __vm_create() directly are left to their own devices. Some tests just pass DEFAULT_GUEST_PHY_PAGES and don't bother with any adjustments, while others mimic the per-vCPU calculations. For vm_create(), and thus __vm_create(), take the number of vCPUs that will be runnable to calculate that number of per-vCPU pages needed for memslot0. To give readers a hint that neither vm_create() nor __vm_create() create vCPUs, name the parameter @nr_runnable_vcpus instead of @nr_vcpus. That also gives readers a hint as to why tests that create larger numbers of vCPUs but never actually run those vCPUs can skip straight to the vm_create_barebones() variant. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- tools/testing/selftests/kvm/lib/kvm_util.c | 57 ++++++++++++++++++++---------- 1 file changed, 38 insertions(+), 19 deletions(-) (limited to 'tools/testing/selftests/kvm/lib/kvm_util.c') diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index afefc48757e6..620c35561122 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -258,11 +258,45 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages) return vm; } -struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint64_t nr_pages) +static uint64_t vm_nr_pages_required(enum vm_guest_mode mode, + uint32_t nr_runnable_vcpus, + uint64_t extra_mem_pages) { - struct kvm_vm *vm; + uint64_t nr_pages; + + TEST_ASSERT(nr_runnable_vcpus, + "Use vm_create_barebones() for VMs that _never_ have vCPUs\n"); + + TEST_ASSERT(nr_runnable_vcpus <= kvm_check_cap(KVM_CAP_MAX_VCPUS), + "nr_vcpus = %d too large for host, max-vcpus = %d", + nr_runnable_vcpus, kvm_check_cap(KVM_CAP_MAX_VCPUS)); + + nr_pages = DEFAULT_GUEST_PHY_PAGES; + nr_pages += nr_runnable_vcpus * DEFAULT_STACK_PGS; + + /* + * Account for the number of pages needed for the page tables. The + * maximum page table size for a memory region will be when the + * smallest page size is used. Considering each page contains x page + * table descriptors, the total extra size for page tables (for extra + * N pages) will be: N/x+N/x^2+N/x^3+... which is definitely smaller + * than N/x*2. + */ + nr_pages += (nr_pages + extra_mem_pages) / PTES_PER_MIN_PAGE * 2; - nr_pages = vm_adjust_num_guest_pages(mode, nr_pages); + TEST_ASSERT(nr_runnable_vcpus <= kvm_check_cap(KVM_CAP_MAX_VCPUS), + "Host doesn't support %d vCPUs, max-vcpus = %d", + nr_runnable_vcpus, kvm_check_cap(KVM_CAP_MAX_VCPUS)); + + return vm_adjust_num_guest_pages(mode, nr_pages); +} + +struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus, + uint64_t nr_extra_pages) +{ + uint64_t nr_pages = vm_nr_pages_required(mode, nr_runnable_vcpus, + nr_extra_pages); + struct kvm_vm *vm; vm = ____vm_create(mode, nr_pages); @@ -297,27 +331,12 @@ struct kvm_vm *__vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus uint64_t extra_mem_pages, void *guest_code, struct kvm_vcpu *vcpus[]) { - uint64_t vcpu_pages, extra_pg_pages, pages; struct kvm_vm *vm; int i; TEST_ASSERT(!nr_vcpus || vcpus, "Must provide vCPU array"); - /* The maximum page table size for a memory region will be when the - * smallest pages are used. Considering each page contains x page - * table descriptors, the total extra size for page tables (for extra - * N pages) will be: N/x+N/x^2+N/x^3+... which is definitely smaller - * than N/x*2. - */ - vcpu_pages = nr_vcpus * DEFAULT_STACK_PGS; - extra_pg_pages = (DEFAULT_GUEST_PHY_PAGES + extra_mem_pages + vcpu_pages) / PTES_PER_MIN_PAGE * 2; - pages = DEFAULT_GUEST_PHY_PAGES + vcpu_pages + extra_pg_pages; - - TEST_ASSERT(nr_vcpus <= kvm_check_cap(KVM_CAP_MAX_VCPUS), - "nr_vcpus = %d too large for host, max-vcpus = %d", - nr_vcpus, kvm_check_cap(KVM_CAP_MAX_VCPUS)); - - vm = __vm_create(mode, pages); + vm = __vm_create(mode, nr_vcpus, extra_mem_pages); for (i = 0; i < nr_vcpus; ++i) vcpus[i] = vm_vcpu_add(vm, i, guest_code); -- cgit v1.2.3