> On 17. Sep 2026, at 00:12, Mohamed Mediouni <[email protected]> wrote:
>
>
>
>> On 16. Sep 2026, at 23:49, Doug Cook (WINDOWS) <[email protected]> wrote:
>>
>> whpx_arm_get_ipa_bit_size() declares WHV_CAPABILITY whpx_cap on the
>> stack and initializes it only via WHvGetCapability(). If that fails, the
>> error is reported but execution falls through to
>> round_down_to_parange_bit_size(whpx_cap.PhysicalAddressWidth), reading
>> an uninitialized value.
>
> Hi,
>
> We have default values on the stack as initialised as 0 in QEMU.
>
>>
>> round_down_to_parange_index() searches pamax_map[] for the largest entry
>> that is <= the requested size and ends in g_assert_not_reached(). The
>> smallest valid PARange is 32, so any smaller value aborts QEMU.
>>
>> Fix by setting PhysicalAddressWidth to 32, the smallest
>> architecturally valid PARange.
>
> Where are you getting this condition? Is a certain Windows release broken
> there that I’m not aware of?
>
> Or is the hypervisor present check not happening early enough?
(On-list)
TL;DR at the end:
During a rebase before the initial WHPX merge, the fix for this
was dropped by mistake instead of a proper squash as was intended.
It was "whpx: arm64: check for physical address width after WHPX availability"
at
https://lists.gnu.org/archive/html/qemu-devel/2025-10/msg07939.html
So I resubmitted that commit now.
>> Behaviour then becomes defined, and
>> where the guest memory map fits within that range initialization
>> continues on to the accelerator capability checks and their more
>> specific error messages.
>>
>> Fixes: ea475a5ebb00 ("whpx: arm64: clamp down IPA size")
>>
>> Signed-off-by: Doug Cook <[email protected]>
>> ---
>> target/arm/whpx/whpx-all.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/target/arm/whpx/whpx-all.c b/target/arm/whpx/whpx-all.c
>> index d106400686..dc70b33bc0 100644
>> --- a/target/arm/whpx/whpx-all.c
>> +++ b/target/arm/whpx/whpx-all.c
>> @@ -663,6 +663,7 @@ uint32_t whpx_arm_get_ipa_bit_size(void)
>> if (FAILED(hr)) {
>> error_report("WHPX: failed to get supported "
>> "physical address width, hr=%08lx", hr);
>> + whpx_cap.PhysicalAddressWidth = 32;
>> }
>>
>> /*
>> --
>> 2.55.0.vfs.0.8
>
>
