Hi Itaru,
On Tue, 8 Sept 2026 at 02:44, Itaru Kitayama <[email protected]> wrote:
...
> > This changes what level means for the existing three-level modes:
> > level 0 used to return the top-level entry and now trips the assert,
> > level 1 used to return the leaf and now returns the top level. No
> > caller in tree asks for either of those two levels, and the new
> > numbering matches the architecture.
>
> Yes, as you checked this change won't break current tests, so if you
> have better comments I will replace it with yours.
The code comment reads fine. What's worth adding is a commit-message
note on the behavior change:
For 3-level (64K) modes this renumbers the levels to match the
architecture: level 0 is no longer valid, level 1 is the top entry.
No in-tree caller passes those levels.
...
> Yes, I've dropped the _va_size() function and instead, expanded a bit
> as you suggested the aarch64_get_supported_page_sizes() to check if vcpu
> can address upto 52-bit VA space or not (48-bit max).
Sounds good. One thing for v2: 52-bit VA support is per-granule, so a
single 52-vs-48 result won't hold across granules.
ID_AA64MMFR2_EL1.VARange is the 64K indicator. 4K and 16K get 52-bit
VA from LPA2.
Cheers,
/fuad
> Thanks,
> Itaru.
> >
> > Cheers,
> > /fuad
> >
> >
> > > +{
> > > + struct kvm_vcpu_init preferred_init = {};
> > > + int kvm_fd, vm_fd, vcpu_fd, err;
> > > + u64 val;
> > > + u32 va_range;
> > > + struct kvm_one_reg reg = {
> > > + .id = KVM_ARM64_SYS_REG(SYS_ID_AA64MMFR2_EL1),
> > > + .addr = (u64)&val,
> > > + };
> > > +
> > > + kvm_fd = open_kvm_dev_path_or_exit();
> > > + vm_fd = __kvm_ioctl(kvm_fd, KVM_CREATE_VM, NULL);
> > > + TEST_ASSERT(vm_fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_VM, vm_fd));
> > > +
> > > + vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0);
> > > + TEST_ASSERT(vcpu_fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_VCPU,
> > > vcpu_fd));
> > > +
> > > + err = ioctl(vm_fd, KVM_ARM_PREFERRED_TARGET, &preferred_init);
> > > + TEST_ASSERT(err == 0, KVM_IOCTL_ERROR(KVM_ARM_PREFERRED_TARGET,
> > > err));
> > > +
> > > + err = ioctl(vcpu_fd, KVM_ARM_VCPU_INIT, &preferred_init);
> > > + TEST_ASSERT(err == 0, KVM_IOCTL_ERROR(KVM_ARM_VCPU_INIT, err));
> > > +
> > > + err = ioctl(vcpu_fd, KVM_GET_ONE_REG, ®);
> > > + TEST_ASSERT(err == 0, KVM_IOCTL_ERROR(KVM_GET_ONE_REG, err));
> > > +
> > > + va_range = FIELD_GET(ID_AA64MMFR2_EL1_VARange, val);
> > > +
> > > + close(vcpu_fd);
> > > + close(vm_fd);
> > > + close(kvm_fd);
> > > +
> > > + return va_range >= ID_AA64MMFR2_EL1_VARange_52 ? 52 : 48;
> > > +}
> > > +
> > > void aarch64_get_supported_page_sizes(u32 ipa, u32 *ipa4k,
> > > u32 *ipa16k, u32 *ipa64k)
> > > {
> > >
> > > --
> > > 2.43.0
> > >
