On 7/31/2025 3:26 AM, Ashish Kalra wrote: > From: Ashish Kalra <ashish.kalra@xxxxxxx> > > After a panic if SNP is enabled in the previous kernel then the kdump > kernel boots with IOMMU SNP enforcement still enabled. > > IOMMU command buffers and event buffer registers remain locked and > exclusive to the previous kernel. Attempts to enable command and event > buffers in the kdump kernel will fail, as hardware ignores writes to > the locked MMIO registers as per AMD IOMMU spec Section 2.12.2.1. > > Skip enabling command buffers and event buffers for kdump boot as they > are already enabled in the previous kernel. > > Tested-by: Sairaj Kodilkar <sarunkod@xxxxxxx> > Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx> Reviewed-by: Vasant Hegde <vasant.hegde@xxxxxxx> -Vasant
