Hi Wolfgang,
On 5/15/21 9:28 PM, Wolfgang Müller wrote:
Hi!
First of all, apologies if this is the wrong place to post a problem
report. I figured since I was going to reference a particular commit
anyway I might as well reply to the patch series that (seemed to have)
introduced the problem.
From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
[ Upstream commit a8ce9ebbecdfda3322bbcece6b3b25888217f8e3 ]
The Access/Dirty bits in the first level page table entry will be set
whenever a page table entry was used for address translation or write
permission was successfully translated. This is always true when using
the first-level page table for kernel IOVA. Instead of wasting hardware
cycles to update the certain bits, it's better to set them up at the
beginning.
This commit seems to trigger a kernel panic very early in boot for me in
5.10.37 (36 is fine):
It seems due to the back-ported patch:
- if (!sg) {
- sg_res = nr_pages;
- pteval = ((phys_addr_t)phys_pfn << VTD_PAGE_SHIFT) | attr;
+ if (domain->domain.type == IOMMU_DOMAIN_DMA) {
+ attr |= DMA_FL_PTE_ACCESS;
+ if (prot & DMA_PTE_WRITE)
+ attr |= DMA_FL_PTE_DIRTY;
+ }
}
+ pteval = ((phys_addr_t)phys_pfn << VTD_PAGE_SHIFT) | attr;
Greg, do you want me to rework this patch, or submit an incremental fix?
Best regards,
baolu
