On Tue, Oct 21, 2025 at 03:34:22PM -0700, Jim Mattson wrote:
On Wed, Oct 15, 2025 at 2:23 PM Yosry Ahmed yosry.ahmed@linux.dev 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/lib/x86/vmx.c b/tools/testing/selftests/kvm/lib/x86/vmx.c index d4d1208dd023..1b6d4a007798 100644 --- a/tools/testing/selftests/kvm/lib/x86/vmx.c +++ b/tools/testing/selftests/kvm/lib/x86/vmx.c @@ -401,11 +401,12 @@ void __nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm, struct eptPageTableEntry *pt = vmx->eptp_hva, *pte; uint16_t index;
TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use ""unknown or unsupported guest mode, mode: 0x%x", vm->mode);
TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K ||vm->mode == VM_MODE_PXXV57_4K,"Unknown or unsupported guest mode: 0x%x", vm->mode); TEST_ASSERT((nested_paddr >> 48) == 0,
"Nested physical address 0x%lx requires 5-level paging",
"Nested physical address 0x%lx is > 48-bits and requires 5-level EPT",Shouldn't this assertion be updated now? We technically support 5-level EPT so it should only fire if the mode is VM_MODE_PXXV48_4K. Maybe we should use vm->va_bits?
I did update the assertion! :)
init_vmcs_control_fields() hardcodes a page-walk-length of 4 in the EPTP, and the loop in __nested_pg_map() counts down from PG_LEVEL_512G. There is no support for 5-level EPT here.
__nested_pg_map() will be gone with the series [1] moving nested mappings to use __virt_pg_map(), and with your series the latter does support 5-level EPTs. init_vmcs_control_fields() still hardcodes a page-walk-length of 4 tho.
I actually just realized, my series will already drop these assertions and rely on the ones in __virt_pg_map(), which do use vm->page_shift, so the assertion won't fire if init_vmcs_control_fields() starts using 5-level EPTs.
TL;DR nothing to do here.
[1]https://lore.kernel.org/kvm/20251021074736.1324328-1-yosry.ahmed@linux.dev/
nested_paddr); TEST_ASSERT((nested_paddr % page_size) == 0, "Nested physical address not on page boundary,\n"-- 2.51.0.470.ga7dc726c21-goog