On Wed, Oct 15, 2025, Yosry Ahmed wrote:
On Wed, Sep 17, 2025 at 02:48:39PM -0700, Jim Mattson wrote:
Add a new VM mode, VM_MODE_PXXV57_4K, to support tests that require 5-level paging on x86. This mode sets up a 57-bit virtual address space and sets CR4.LA57 in the guest.
Signed-off-by: Jim Mattson jmattson@google.com
.../testing/selftests/kvm/include/kvm_util.h | 1 + tools/testing/selftests/kvm/lib/kvm_util.c | 21 +++++++++++++++++ .../testing/selftests/kvm/lib/x86/processor.c | 23 ++++++++++++------- tools/testing/selftests/kvm/lib/x86/vmx.c | 7 +++--- 4 files changed, 41 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h index 23a506d7eca3..b6ea5d966715 100644 --- a/tools/testing/selftests/kvm/include/kvm_util.h +++ b/tools/testing/selftests/kvm/include/kvm_util.h @@ -175,6 +175,7 @@ enum vm_guest_mode { VM_MODE_P40V48_16K, VM_MODE_P40V48_64K, VM_MODE_PXXV48_4K, /* For 48bits VA but ANY bits PA */
- VM_MODE_PXXV57_4K, /* For 48bits VA but ANY bits PA */ VM_MODE_P47V64_4K, VM_MODE_P44V64_4K, VM_MODE_P36V48_4K,
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index c3f5142b0a54..6b0e499c6e91 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -232,6 +232,7 @@ const char *vm_guest_mode_string(uint32_t i) [VM_MODE_P40V48_16K] = "PA-bits:40, VA-bits:48, 16K pages", [VM_MODE_P40V48_64K] = "PA-bits:40, VA-bits:48, 64K pages", [VM_MODE_PXXV48_4K] = "PA-bits:ANY, VA-bits:48, 4K pages",
[VM_MODE_PXXV57_4K] = "PA-bits:ANY, VA-bits:57, 4K pages",@@ -259,6 +260,7 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = { [VM_MODE_P40V48_16K] = { 40, 48, 0x4000, 14 }, [VM_MODE_P40V48_64K] = { 40, 48, 0x10000, 16 }, [VM_MODE_PXXV48_4K] = { 0, 0, 0x1000, 12 },
- [VM_MODE_PXXV57_4K] = { 0, 0, 0x1000, 12 }, [VM_MODE_P47V64_4K] = { 47, 64, 0x1000, 12 }, [VM_MODE_P44V64_4K] = { 44, 64, 0x1000, 12 }, [VM_MODE_P36V48_4K] = { 36, 48, 0x1000, 12 },
@@ -358,6 +360,25 @@ struct kvm_vm *____vm_create(struct vm_shape shape) vm->va_bits = 48; #else TEST_FAIL("VM_MODE_PXXV48_4K not supported on non-x86 platforms");
We should probably update TEST_ASSERT(vm->va_bits == 48 || vm->va_bits == 57) above to only assert 48 bits now, right?
No, because CPUID reports the _max_ virtual address width. In theory, the assert could be ">= 48", but in practice x86-64 only supports 48-bit and 57-bit VAs, so selftests are paranoid and are sanity checking KVM at the same time.