On aarch64 hosts with 64K pages, the platform bus MMIO allocator can
allocate the 1KB "tpm-ppi" region at offsets not aligned to the host
page size, triggering a noisy VFIO IOMMU warning at VM startup:

  vfio_listener_valid_section received unaligned region tpm-ppi
    iova=0xc005000 offset_within_region=0x0
    qemu_real_host_page_size=0x10000

Commit 851d6d1a0ff2 ("vfio/common: remove spurious tpm-crb-cmd
misalignment warning") suppressed this for TPM CRB devices via a
TPM_IS_CRB(owner) check. However, this misses "tpm-ppi" regions owned
by other TPM types like SysBus/ISA tpm-tis devices.

Avoid enumerating every TPM device type by matching the "tpm-ppi"
memory region name directly in vfio_known_safe_misalignment().

Signed-off-by: Cedric Le Goater <clg@redhat.com>
---
 hw/vfio/listener.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index c19600e980a8d02217b5d9df4aca8f879ab2c5d5..c76ba285ddb7ef4f93bb081e67de47b3aecbe212 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -355,8 +355,10 @@ static void vfio_ram_discard_unregister_listener(VFIOContainer *bcontainer,
 static bool vfio_known_safe_misalignment(MemoryRegionSection *section)
 {
     MemoryRegion *mr = section->mr;
+    const char *name = memory_region_name(mr);
 
-    if (!TPM_IS_CRB(mr->owner)) {
+    if (!TPM_IS_CRB(mr->owner) &&
+        !(name && strcmp(name, "tpm-ppi") == 0)) {
         return false;
     }
 
-- 
2.54.0

On Wed, 1 Jul 2026 at 09:09, Cédric Le Goater <clg@redhat.com> wrote:
>
> On aarch64 hosts with 64K pages, the platform bus MMIO allocator can
> allocate the 1KB "tpm-ppi" region at offsets not aligned to the host
> page size, triggering a noisy VFIO IOMMU warning at VM startup:
>
>   vfio_listener_valid_section received unaligned region tpm-ppi
>     iova=0xc005000 offset_within_region=0x0
>     qemu_real_host_page_size=0x10000
>
> Commit 851d6d1a0ff2 ("vfio/common: remove spurious tpm-crb-cmd
> misalignment warning") suppressed this for TPM CRB devices via a
> TPM_IS_CRB(owner) check. However, this misses "tpm-ppi" regions owned
> by other TPM types like SysBus/ISA tpm-tis devices.
>
> Avoid enumerating every TPM device type by matching the "tpm-ppi"
> memory region name directly in vfio_known_safe_misalignment().
>
> Signed-off-by: Cedric Le Goater <clg@redhat.com>
> ---
>  hw/vfio/listener.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
> index c19600e980a8d02217b5d9df4aca8f879ab2c5d5..c76ba285ddb7ef4f93bb081e67de47b3aecbe212 100644
> --- a/hw/vfio/listener.c
> +++ b/hw/vfio/listener.c
> @@ -355,8 +355,10 @@ static void vfio_ram_discard_unregister_listener(VFIOContainer *bcontainer,
>  static bool vfio_known_safe_misalignment(MemoryRegionSection *section)
>  {
>      MemoryRegion *mr = section->mr;
> +    const char *name = memory_region_name(mr);
>
> -    if (!TPM_IS_CRB(mr->owner)) {
> +    if (!TPM_IS_CRB(mr->owner) &&
> +        !(name && strcmp(name, "tpm-ppi") == 0)) {
>          return false;
>      }

I think this is the wrong approach, see my comments on the
other email thread. vfio should not be building up some kind
of whitelist of "this specific not-page-aligned RAM is OK",
because a not-page-aligned RAM backed MMIO region is in general
a normal thing to have.

thanks
-- PMM

On 7/1/26 12:26, Peter Maydell wrote:
> On Wed, 1 Jul 2026 at 09:09, Cédric Le Goater <clg@redhat.com> wrote:
>>
>> On aarch64 hosts with 64K pages, the platform bus MMIO allocator can
>> allocate the 1KB "tpm-ppi" region at offsets not aligned to the host
>> page size, triggering a noisy VFIO IOMMU warning at VM startup:
>>
>>    vfio_listener_valid_section received unaligned region tpm-ppi
>>      iova=0xc005000 offset_within_region=0x0
>>      qemu_real_host_page_size=0x10000
>>
>> Commit 851d6d1a0ff2 ("vfio/common: remove spurious tpm-crb-cmd
>> misalignment warning") suppressed this for TPM CRB devices via a
>> TPM_IS_CRB(owner) check. However, this misses "tpm-ppi" regions owned
>> by other TPM types like SysBus/ISA tpm-tis devices.
>>
>> Avoid enumerating every TPM device type by matching the "tpm-ppi"
>> memory region name directly in vfio_known_safe_misalignment().
>>
>> Signed-off-by: Cedric Le Goater <clg@redhat.com>
>> ---
>>   hw/vfio/listener.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
>> index c19600e980a8d02217b5d9df4aca8f879ab2c5d5..c76ba285ddb7ef4f93bb081e67de47b3aecbe212 100644
>> --- a/hw/vfio/listener.c
>> +++ b/hw/vfio/listener.c
>> @@ -355,8 +355,10 @@ static void vfio_ram_discard_unregister_listener(VFIOContainer *bcontainer,
>>   static bool vfio_known_safe_misalignment(MemoryRegionSection *section)
>>   {
>>       MemoryRegion *mr = section->mr;
>> +    const char *name = memory_region_name(mr);
>>
>> -    if (!TPM_IS_CRB(mr->owner)) {
>> +    if (!TPM_IS_CRB(mr->owner) &&
>> +        !(name && strcmp(name, "tpm-ppi") == 0)) {
>>           return false;
>>       }
> 
> I think this is the wrong approach, see my comments on the
> other email thread. vfio should not be building up some kind
> of whitelist of "this specific not-page-aligned RAM is OK",
> because a not-page-aligned RAM backed MMIO region is in general
> a normal thing to have.

We should warn for only VFIO-owned regions. I agree.

Forget this patch. It's minor anyway. I will see how the listener
can be improved to remove vfio_known_safe_misalignment()

Thanks,

C.