[PATCH v2] iommu/vt-d: respect max guest address width in agaw

[PATCH v2] iommu/vt-d: respect max guest address width in agaw

[Jacob Pan]

Supported guest address witdh (SGAW) only indicates
what the iommu's capabilities are wrt page table levels
for second level page-tables. IOMMU should pick the
right level depending on the Maximum Guest Address Width
(MGAW).

For pass-through translation type, address width must be
programmed with the largest AGAW supported by the HW.

Reported-by: Ramos Falcon, Ernesto R <ernesto.r.ramos.falcon-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Ashok Raj <ashok.raj-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Jacob Pan <jacob.jun.pan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 drivers/iommu/intel-iommu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 140d6ab..f16db3b 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -719,7 +719,11 @@ int iommu_calculate_max_sagaw(struct intel_iommu *iommu)
  */
 int iommu_calculate_agaw(struct intel_iommu *iommu)
 {
-	return __iommu_calculate_agaw(iommu, DEFAULT_DOMAIN_ADDRESS_WIDTH);
+	unsigned long mgaw;
+
+	/* Respect Max Guest Address Width */
+	mgaw = min(cap_mgaw(iommu->cap), DEFAULT_DOMAIN_ADDRESS_WIDTH);
+	return __iommu_calculate_agaw(iommu, mgaw);
 }
 
 /* This functionin only returns single iommu in a domain */
-- 
2.7.4

Re: [PATCH v2] iommu/vt-d: respect max guest address width in agaw

[Joerg Roedel]

On Tue, Nov 06, 2018 at 02:47:15PM -0800, Jacob Pan wrote:
>  drivers/iommu/intel-iommu.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

Applied, thanks.

Re: [PATCH v2] iommu/vt-d: respect max guest address width in agaw

[Jacob Pan]

On Wed, 7 Nov 2018 17:04:28 +0100
Joerg Roedel <joro@8bytes.org> wrote:

> On Tue, Nov 06, 2018 at 02:47:15PM -0800, Jacob Pan wrote:
> >  drivers/iommu/intel-iommu.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)  
> 
> Applied, thanks.

Hi Joerg,
We have found some issues with this patch on some platforms. Please
disregard this patch.

The intent of this patch was to fix some IOMMU with max address of 48
but SAGAW of both 48 and 57 bits. Need to do more investigation in the
page table level calculation and context address width setup. Sorry
about that.

Jacob

Re: [PATCH v2] iommu/vt-d: respect max guest address width in agaw

[Joerg Roedel]

On Wed, Nov 07, 2018 at 02:12:25PM -0800, Jacob Pan wrote:
> We have found some issues with this patch on some platforms. Please
> disregard this patch.

Patch dropped.