Messages in this thread | | | Subject | Re: Question about domain_init (v5.3-v5.7) | From | Lu Baolu <> | Date | Thu, 26 Nov 2020 19:01:36 +0800 |
| |
Hi Jerry,
On 2020/11/26 4:27, Jerry Snitselaar wrote: > > Is there a reason we check the requested guest address width against the > iommu's mgaw, instead of the agaw that we already know for the iommu? > I've run into a case with a new system where the mgaw reported is 57, > but if they set PAE to 46 instead of 52 in the bios, then sagaw reports > the highest supported agaw is 48 and the domain_init code fails here. In
Isn't this a platform bug? If it's too late to fix it in the BIOS, you maybe have to add a platform specific quirk to set mgaw to the highest supported agaw?
Best regards, baolu
> other places like prepare_domain_attach_device, the dmar domain agaw > gets adjusted down to the iommu agaw. The agaw of the iommu gets > determined based off what is reported for sagaw. I'm wondering if it > can't instead do: > > --- > drivers/iommu/intel-iommu.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 6ca5c92ef2e5..a8e41ec36d9e 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -1862,8 +1862,8 @@ static int domain_init(struct dmar_domain *domain, struct intel_iommu *iommu, > domain_reserve_special_ranges(domain); > > /* calculate AGAW */ > - if (guest_width > cap_mgaw(iommu->cap)) > - guest_width = cap_mgaw(iommu->cap); > + if (guest_width > agaw_to_width(iommu->agaw)) > + guest_width = agaw_to_width(iommu->agaw); > domain->gaw = guest_width; > adjust_width = guestwidth_to_adjustwidth(guest_width); > agaw = width_to_agaw(adjust_width); > -- > 2.27.0 > > > Thoughts? With the former code the ehci device for the ilo fails when > trying to get a private domain. > > Thanks, > Jerry >
| |