On Tue, Sep 06, 2022, Ricardo Koller wrote:
> @@ -637,19 +658,45 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> vm_paddr_t paddr_min, uint32_t memslot);
> vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
>
> +struct kvm_vm_mem_params {
> + enum vm_guest_mode mode;
> +
> + struct {
> + enum vm_mem_backing_src_type src_type;
> + uint64_t guest_paddr;
> + /*
> + * KVM region slot (same meaning as in struct
> + * kvm_userspace_memory_region).
> + */
> + uint32_t slot;
> + uint64_t npages;
> + uint32_t flags;
> + bool enabled;
"enabled" is unnecessary, just have ____vm_create() skip over regions with npages=0.
Likely ends up being a moot point though.
> + } region[NR_MEM_REGIONS];
> +
> + /* Each region type points to a region in the above array. */
> + uint16_t region_idx[NR_MEM_REGIONS];
Eww. This is going to be super confusing and it's one more thing for tests to
screw up. And open coding the indices for region[] is beyond gross.
> +};
> +
> +extern struct kvm_vm_mem_params kvm_vm_mem_default;
> +
> /*
> * ____vm_create() does KVM_CREATE_VM and little else. __vm_create() also
> * loads the test binary into guest memory and creates an IRQ chip (x86 only).
> * __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to
> * calculate the amount of memory needed for per-vCPU data, e.g. stacks.
> */
> -struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
> +struct kvm_vm *____vm_create(struct kvm_vm_mem_params *mem_params);
> struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
> uint64_t nr_extra_pages);
>
> static inline struct kvm_vm *vm_create_barebones(void)
> {
> - return ____vm_create(VM_MODE_DEFAULT, 0);
> + struct kvm_vm_mem_params params_wo_memslots = {
> + .mode = kvm_vm_mem_default.mode,
> + };
> +
> + return ____vm_create(¶ms_wo_memslots);
Very related to the above complaints, this is rather ugly. I liked the idea of
passing a struct to __vm_create(), but passing it to ____vm_create() feels extremely
forced.
In an ideal world, my preference would still be to modify __vm_create() to take the
struct so that a test that wants to utilize different memslots doesn't need to
manually duplicate all the other stuff in __vm_create(), but that might end up
being too forced as well. For now, I'm ok punting on that so the page_fault_test
can get merged.
Looking at this with fresh eyes, there's simply no reason ____vm_create() should be
creating memslots. If this series first moves the memslot creation into __vm_create()
where it belongs (patch below), then there's no need to force ____vm_create() to take
a struct. And if we punt on refactoring __vm_create(), then there's no need to
add kvm_vm_mem_default and no real need to add struct kvm_vm_mem_params either.
If/when there's a second test that wants fine-grained control over memslots then
we can figure out a proper API to share between page_fault_test and whatever the
new test is, but for now if page_fault_test is going to call ____vm_create()
directly, then I think it's easier to forego the common API and just have page_fault_test
and __vm_create() open code setting vm->memslots.
Alternatively, if we really want a common API right away, then we can add a helper
to populate the memory region + vm->memslots.
Option A (open code):
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;
int i;
vm = ____vm_create(mode);
vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0);
for (i = 0; i < NR_MEM_REGIONS; i++)
vm->memslots[i] = 0;
kvm_vm_elf_load(vm, program_invocation_name);
#ifdef __x86_64__
vm_create_irqchip(vm);
#endif
return vm;
}
...
enum pf_test_memslots {
CODE_MEMSLOT,
PAGE_TABLE_MEMSLOT,
DATA_MEMSLOT,
}
/* Create a code memslot at pfn=0, and data and PT ones at max_gfn. */
static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
{
uint64_t backing_src_pagesz = get_backing_src_pagesz(p->src_type);
uint64_t guest_page_size = vm_guest_mode_params[mode].page_size;
uint64_t max_gfn = get_max_gfn(mode);
/* Enough for 2M of code when using 4K guest pages. */
uint64_t code_npages = 512;
uint64_t pt_size, data_size, data_gpa;
/*
* This test requires 1 pgd, 2 pud, 4 pmd, and 6 pte pages when using
* VM_MODE_P48V48_4K. Note that the .text takes ~1.6MBs. That's 13
* pages. VM_MODE_P48V48_4K is the mode with most PT pages; let's use
* twice that just in case.
*/
pt_size = 26 * guest_page_size;
/* memslot sizes and gpa's must be aligned to the backing page size */
pt_size = align_up(pt_size, backing_src_pagesz);
data_size = align_up(guest_page_size, backing_src_pagesz);
data_gpa = (max_gfn * guest_page_size) - data_size;
data_gpa = align_down(data_gpa, backing_src_pagesz);
vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, CODE_MEMSLOT,
code_npages, 0);
vm->memslots[MEM_REGION_CODE] = CODE_MEMSLOT;
vm_userspace_mem_region_add(vm, p->src_type, data_gpa - pt_size,
PAGE_TABLE_MEMSLOT, pt_size / guest_page_size,
p->test_desc->pt_memslot_flags);
vm->memslots[MEM_REGION_PT] = PAGE_TABLE_MEMSLOT;
vm_userspace_mem_region_add(vm, p->src_type, data_gpa, DATA_MEMSLOT,
data_size / guest_page_size,
p->test_desc->data_memslot_flags);
vm->memslots[MEM_REGION_PT] = DATA_MEMSLOT;
}
static void run_test(enum vm_guest_mode mode, void *arg)
{
struct test_params *p = (struct test_params *)arg;
struct test_desc *test = p->test_desc;
struct kvm_vm *vm;
struct kvm_vcpu *vcpu;
struct uffd_desc *pt_uffd, *data_uffd;
print_test_banner(mode, p);
vm = ____vm_create(mode);
setup_memslots(vm, p);
kvm_vm_elf_load(vm, program_invocation_name);
vcpu = vm_vcpu_add(vm, 0, guest_code);
...
}
Option B (helper):
enum kvm_mem_region_mask {
MEM_REGION_CODE_MASK = BIT(MEM_REGION_CODE),
MEM_REGION_PT_MASK = BIT(MEM_REGION_PT),
MEM_REGION_DATA_MASK = BIT(MEM_REGION_DATA),
MEM_REGION_ALL_MASK = MEM_REGION_CODE_MASK |
MEM_REGION_PT_MASK |
MEM_REGION_DATA_MASK,
};
void kvm_vm_add_mem_region(struct kvm_vm *vm, enum kvm_mem_region_mask type_mask,
enum vm_mem_backing_src_type src_type, uint32_t slot,
uint64_t guest_paddr, uint64_t nr_pages, uint32_t flags)
{
int i;
vm_userspace_mem_region_add(vm, src_type, guest_paddr, slot, nr_pages, 0);
for (i = 0; i < NR_MEM_REGIONS; i++) {
if (BIT(i) & type_mask)
vm->memslots[i] = slot;
}
}
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;
int i;
vm = ____vm_create(mode);
kvm_vm_add_mem_region(vm, MEM_REGION_ALL_MASK, VM_MEM_SRC_ANONYMOUS, 0,
0, nr_pages, 0);
kvm_vm_elf_load(vm, program_invocation_name);
#ifdef __x86_64__
vm_create_irqchip(vm);
#endif
return vm;
}
static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
{
...
kvm_vm_add_mem_region(vm, MEM_REGION_CODE_MASK, VM_MEM_SRC_ANONYMOUS,
CODE_MEMSLOT, 0, code_npages, 0);
kvm_vm_add_mem_region(vm, MEM_REGION_PT_MASK p->src_type,
PAGE_TABLE_MEMSLOT, data_gpa - pt_size,
pt_size / guest_page_size,
p->test_desc->pt_memslot_flags);
kvm_vm_add_mem_region(vm, MEM_REGION_DATA_MASK, p->src_type,
DATA_MEMSLOT, data_gpa,
data_size / guest_page_size,
p->test_desc->data_memslot_flags);
}
---
.../testing/selftests/kvm/include/kvm_util_base.h | 4 ++--
tools/testing/selftests/kvm/lib/kvm_util.c | 15 +++++++--------
2 files changed, 9 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 24fde97f6121..107cb87908f8 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -642,13 +642,13 @@ vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
* __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to
* calculate the amount of memory needed for per-vCPU data, e.g. stacks.
*/
-struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
+struct kvm_vm *____vm_create(enum vm_guest_mode mode);
struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
uint64_t nr_extra_pages);
static inline struct kvm_vm *vm_create_barebones(void)
{
- return ____vm_create(VM_MODE_DEFAULT, 0);
+ return ____vm_create(VM_MODE_DEFAULT);
}
static inline struct kvm_vm *vm_create(uint32_t nr_runnable_vcpus)
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 9889fe0d8919..c761422faa17 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -143,13 +143,10 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
_Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
"Missing new mode params?");
-struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
+struct kvm_vm *____vm_create(enum vm_guest_mode mode)
{
struct kvm_vm *vm;
- pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
- vm_guest_mode_string(mode), nr_pages);
-
vm = calloc(1, sizeof(*vm));
TEST_ASSERT(vm != NULL, "Insufficient Memory");
@@ -245,9 +242,6 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
/* Allocate and setup memory for guest. */
vm->vpages_mapped = sparsebit_alloc();
- if (nr_pages != 0)
- vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
- 0, 0, nr_pages, 0);
return vm;
}
@@ -294,7 +288,12 @@ struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
nr_extra_pages);
struct kvm_vm *vm;
- vm = ____vm_create(mode, nr_pages);
+ pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
+ vm_guest_mode_string(mode), nr_pages);
+
+ vm = ____vm_create(mode);
+
+ vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0);
kvm_vm_elf_load(vm, program_invocation_name);
base-commit: 372d07084593dc7a399bf9bee815711b1fb1bcf2
--
