Hi Suzuki,
On 4/2/19 11:47 AM, Suzuki K Poulose wrote:
> On Mon, Apr 01, 2019 at 07:10:37PM +0200, Auger Eric wrote:
>> Hi Suzuki,
>>
>> On 3/28/19 2:36 PM, Marc Zyngier wrote:
>>> From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>>>
>>> commit 6794ad5443a2118 ("KVM: arm/arm64: Fix unintended stage 2 PMD mappings")
>>> made the checks to skip huge mappings, stricter. However it introduced
>>> a bug where we still use huge mappings, ignoring the flag to
>>> use PTE mappings, by not reseting the vma_pagesize to PAGE_SIZE.
>>>
>>> Also, the checks do not cover the PUD huge pages, that was
>>> under review during the same period. This patch fixes both
>>> the issues.
>>
>> I face a regression with this patch. My guest gets stuck. I am running
>> on AMD Seattle. Reverting the patch makes things work again for me. I
>> run with qemu. In this scenario I don't use hugepages. I use 64kB page
>> size for both the host and guest.
>
> Hi Eric,
>
> Thanks for the testing. Does the following patch fix the issue for you ?
Yes it does.
Thanks
Eric
>
>
> ---8>---
> kvm: arm: Skip transparent huge pages in unaligned memslots
>
> We silently create stage2 huge mappings for a memslot with
> unaligned IPA and user address.
>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> ---
> virt/kvm/arm/mmu.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index 27c9583..4a22f5b 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -1412,7 +1412,9 @@ static bool transparent_hugepage_adjust(kvm_pfn_t *pfnp, phys_addr_t *ipap)
> * page accordingly.
> */
> mask = PTRS_PER_PMD - 1;
> - VM_BUG_ON((gfn & mask) != (pfn & mask));
> + /* Skip memslots with unaligned IPA and user address */
> + if ((gfn & mask) != (pfn & mask))
> + return false;
> if (pfn & mask) {
> *ipap &= PMD_MASK;
> kvm_release_pfn_clean(pfn);
>
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