Re: [PATCH 0/2] iommu/amd: Use MAX buffer size when SNP is enabled on Family 0x19
Usama Arif <[email protected]>
| Newsgroups | dev.linux.lists.iommu |
|---|---|
| Message-ID | <[email protected]> |
On Thu, 13 Aug 2026 19:28:55 +0530 Vasant Hegde <[email protected]> wrote: > Usama, > > On 8/13/2026 6:48 PM, Usama Arif wrote: > > [You don't often get email from [email protected]. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > > > On Mon, 20 Apr 2026 08:42:02 +0000 Vasant Hegde <[email protected]> wrote: > > > >> This series addresses CVE-2023-20585 [1] by increasing the AMD IOMMU > >> Event log and PPR log buffer sizes to the maximum supported value (512K) > >> on affected CPU families when SNP is enabled. > >> > >> Use MAX buffer size when SNP is enabled on Milan/Genoa. Impacted buffers: > >> - Milan : Event log (PPR/GALog is not supported when SNP is enabled) > >> - Genoa : Event and PPR log (GALog is not supported when SNP is enabled) > >> > > > > Hi, > > > > This series seems to break kexec in our production on Milan hosts with SEV enabled. > > This is on the 6.18.43 stable kernel backport. > > Do you have dmesg? > > > > > If on top of 6.18.43 release, we revert the 2 commits, i.e. > > Revert "iommu/amd: Use maximum PPR log buffer size when SNP is enabled on Family 0x19" > > Revert "iommu/amd: Use maximum Event log buffer size when SNP is enabled on Family 0x19" > > > > kexec starts working again. > > > Could you help in fixing this issue? > > Sure. We will try to reproduce it internally and get back to you. Hi, Just following up, were you able to reproduce this? I was able to trace down the hang to this do while loop [1]. Could this be a firmware bug? We are currently running 1.53 (below shows up in the dmesg). [ 22.245942] ccp 0000:41:00.1: SEV-SNP API:1.53 build:5 [ 22.308933] ccp 0000:41:00.1: SEV API:1.53 build:5 [1] https://elixir.bootlin.com/linux/v7.2/source/arch/x86/virt/svm/sev.c#L1017 Thanks, Usama > > -Vasant > >