Messages in this thread | | | Date | Wed, 16 Nov 2022 04:28:11 -0600 | Subject | Re: [PATCH Part2 v6 14/49] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled | From | "Kalra, Ashish" <> |
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On 11/15/2022 11:19 PM, HORIGUCHI NAOYA(堀口 直也) wrote: > On Tue, Nov 15, 2022 at 04:14:42PM +0100, Vlastimil Babka wrote: >> Cc'ing memory failure folks, the beinning of this subthread is here: >> >> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F3a51840f6a80c87b39632dc728dbd9b5dd444cd7.1655761627.git.ashish.kalra%40amd.com%2F&data=05%7C01%7Cashish.kalra%40amd.com%7C7b2d39d6e2504a8f923608dac792224b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638041727879125176%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=KBJLKhPQP23vmvY%2FNnbjZs8wTJs%2FrF%2BiU54Sdc4Ldx4%3D&reserved=0 >> >> On 11/15/22 00:36, Kalra, Ashish wrote: >>> Hello Boris, >>> >>> On 11/2/2022 6:22 AM, Borislav Petkov wrote: >>>> On Mon, Oct 31, 2022 at 04:58:38PM -0500, Kalra, Ashish wrote: >>>>> if (snp_lookup_rmpentry(pfn, &rmp_level)) { >>>>> do_sigbus(regs, error_code, address, VM_FAULT_SIGBUS); >>>>> return RMP_PF_RETRY; >>>> >>>> Does this issue some halfway understandable error message why the >>>> process got killed? >>>> >>>>> Will look at adding our own recovery function for the same, but that will >>>>> again mark the pages as poisoned, right ? >>>> >>>> Well, not poisoned but PG_offlimits or whatever the mm folks agree upon. >>>> Semantically, it'll be handled the same way, ofc. >>> >>> Added a new PG_offlimits flag and a simple corresponding handler for it. >> >> One thing is, there's not enough page flags to be adding more (except >> aliases for existing) for cases that can avoid it, but as Boris says, if >> using alias to PG_hwpoison it depends what will become confused with the >> actual hwpoison. > > I agree with this. Just defining PG_offlimits as an alias of PG_hwpoison > could break current hwpoison workload. So if you finally decide to go > forward in this direction, you may as well have some indicator to > distinguish the new kind of leaked pages from hwpoisoned pages. > > I don't remember exact thread, but I've read someone writing about similar > kind of suggestion of using memory_failure() to make pages inaccessible in > non-memory error usecase. I feel that it could be possible to generalize > memory_failure() as general-purpose page offlining (by renaming it with
But, doesn't memory_failure() also mark the pages as PG_hwpoison, and then using it for these leaked pages will again cause confusion with actual hwpoison ?
Thanks, Ashish
> hard_offline_page() and making memory_failure() one of the user of it). > > Thanks, > Naoya Horiguchi >
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