From: "Kalra, Ashish" <ashish.kalra@amd.com>
To: Vlastimil Babka <vbabka@suse.cz>,
Michael Roth <michael.roth@amd.com>,
x86@kernel.org
Cc: kvm@vger.kernel.org, linux-coco@lists.linux.dev,
linux-mm@kvack.org, linux-crypto@vger.kernel.org,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
mingo@redhat.com, jroedel@suse.de, thomas.lendacky@amd.com,
hpa@zytor.com, ardb@kernel.org, pbonzini@redhat.com,
seanjc@google.com, vkuznets@redhat.com, jmattson@google.com,
luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com,
pgonda@google.com, peterz@infradead.org,
srinivas.pandruvada@linux.intel.com, rientjes@google.com,
tobin@ibm.com, bp@alien8.de, kirill@shutemov.name,
ak@linux.intel.com, tony.luck@intel.com,
sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com,
jarkko@kernel.org, nikunj.dadhania@amd.com, pankaj.gupta@amd.com,
liam.merwick@oracle.com, zhi.a.wang@intel.com
Subject: Re: [PATCH v1 15/26] x86/sev: Introduce snp leaked pages list
Date: Tue, 9 Jan 2024 16:19:02 -0600 [thread overview]
Message-ID: <5cdd2093-b007-404d-96a8-89b3aa6e6e4b@amd.com> (raw)
In-Reply-To: <f221ad9d-6fc3-466b-bacf-23986b8655f5@suse.cz>
Hello Vlastimil,
On 1/8/2024 4:45 AM, Vlastimil Babka wrote:
> On 12/30/23 17:19, Michael Roth wrote:
>> From: Ashish Kalra <ashish.kalra@amd.com>
>>
>> Pages are unsafe to be released back to the page-allocator, if they
>> have been transitioned to firmware/guest state and can't be reclaimed
>> or transitioned back to hypervisor/shared state. In this case add
>> them to an internal leaked pages list to ensure that they are not freed
>> or touched/accessed to cause fatal page faults.
>>
>> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
>> [mdr: relocate to arch/x86/virt/svm/sev.c]
>> Signed-off-by: Michael Roth <michael.roth@amd.com>
> Hi, sorry I didn't respond in time to the last mail discussing previous
> version in
> https://lore.kernel.org/all/8c1fd8da-912a-a9ce-9547-107ba8a450fc@amd.com/
> due to upcoming holidays.
>
> I would rather avoid the approach of allocating container objects:
> - it's allocating memory when effectively losing memory, a dangerous thing
> - are all the callers and their context ok with GFP_KERNEL?
> - GFP_KERNEL_ACCOUNT seems wrong, why would we be charging this to the
> current process, it's probably not its fault the pages are leaked? Also the
> charging can fail?
> - given the benefit of having leaked pages on a list is basically just
> debugging (i.e. crash dump or drgn inspection) this seems too heavy
>
> I think it would be better and sufficient to use page->lru for order-0 and
> head pages, and simply skip tail pages (possibly with adjusted warning
> message for that case).
>
> Vlastimil
>
> <snip
Considering the above thoughts, this is updated version of
snp_leak_pages(), looking forward to any review comments/feedback you
have on the same:
void snp_leak_pages(u64 pfn, unsigned int npages)
{
struct page *page = pfn_to_page(pfn);
pr_debug("%s: leaking PFN range 0x%llx-0x%llx\n", __func__,
pfn, pfn + npages);
spin_lock(&snp_leaked_pages_list_lock);
while (npages--) {
/*
* Reuse the page's buddy list for chaining into the leaked
* pages list. This page should not be on a free list
currently
* and is also unsafe to be added to a free list.
*/
if ((likely(!PageCompound(page))) || (PageCompound(page) &&
!PageTail(page) && compound_head(page) == page))
/*
* Skip inserting tail pages of compound page as
* page->buddy_list of tail pages is not usable.
*/
list_add_tail(&page->buddy_list,
&snp_leaked_pages_list);
sev_dump_rmpentry(pfn);
snp_nr_leaked_pages++;
pfn++;
page++;
}
spin_unlock(&snp_leaked_pages_list_lock);
}
Thanks, Ashish
next prev parent reply other threads:[~2024-01-09 22:19 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-30 16:19 [PATCH v1 00/26] Add AMD Secure Nested Paging (SEV-SNP) Initialization Support Michael Roth
2023-12-30 16:19 ` [PATCH v1 01/26] x86/cpufeatures: Add SEV-SNP CPU feature Michael Roth
2023-12-31 11:50 ` Borislav Petkov
2023-12-31 16:44 ` Michael Roth
2023-12-30 16:19 ` [PATCH v1 02/26] x86/speculation: Do not enable Automatic IBRS if SEV SNP is enabled Michael Roth
2023-12-30 16:19 ` [PATCH v1 03/26] iommu/amd: Don't rely on external callers to enable IOMMU SNP support Michael Roth
2024-01-04 10:30 ` Borislav Petkov
2024-01-04 10:58 ` Joerg Roedel
2023-12-30 16:19 ` [PATCH v1 04/26] x86/sev: Add the host SEV-SNP initialization support Michael Roth
2024-01-04 11:05 ` Jeremi Piotrowski
2024-01-05 16:09 ` Borislav Petkov
2024-01-05 16:21 ` Borislav Petkov
2024-01-08 16:49 ` Jeremi Piotrowski
2024-01-08 17:04 ` Borislav Petkov
2024-01-09 11:56 ` Jeremi Piotrowski
2024-01-09 12:29 ` Borislav Petkov
2024-01-09 12:44 ` Borislav Petkov
2024-02-14 16:56 ` Jeremi Piotrowski
2024-01-04 11:16 ` Borislav Petkov
2024-01-04 14:42 ` Borislav Petkov
2024-01-05 19:19 ` Borislav Petkov
2024-01-05 21:27 ` Borislav Petkov
2023-12-30 16:19 ` [PATCH v1 05/26] x86/mtrr: Don't print errors if MtrrFixDramModEn is set when SNP enabled Michael Roth
2023-12-30 16:19 ` [PATCH v1 06/26] x86/sev: Add RMP entry lookup helpers Michael Roth
2023-12-30 16:19 ` [PATCH v1 07/26] x86/fault: Add helper for dumping RMP entries Michael Roth
2024-01-10 9:59 ` Borislav Petkov
2024-01-10 20:18 ` Jarkko Sakkinen
2024-01-10 22:14 ` Borislav Petkov
2024-01-10 11:13 ` Borislav Petkov
2024-01-10 15:20 ` Tom Lendacky
2024-01-10 15:27 ` Borislav Petkov
2024-01-10 15:51 ` Tom Lendacky
2024-01-10 15:55 ` Borislav Petkov
2024-01-10 15:10 ` Tom Lendacky
2023-12-30 16:19 ` [PATCH v1 08/26] x86/traps: Define RMP violation #PF error code Michael Roth
2023-12-30 16:19 ` [PATCH v1 09/26] x86/fault: Dump RMP table information when RMP page faults occur Michael Roth
2023-12-30 16:19 ` [PATCH v1 10/26] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Michael Roth
2024-01-12 14:49 ` Borislav Petkov
2023-12-30 16:19 ` [PATCH v1 11/26] x86/sev: Invalidate pages from the direct map when adding them to the RMP table Michael Roth
2024-01-12 19:48 ` Borislav Petkov
2024-01-12 20:00 ` Dave Hansen
2024-01-12 20:07 ` Borislav Petkov
2024-01-12 20:27 ` Vlastimil Babka
2024-01-15 9:06 ` Borislav Petkov
2024-01-15 9:14 ` Vlastimil Babka
2024-01-15 9:16 ` Mike Rapoport
2024-01-15 9:20 ` Borislav Petkov
2024-01-12 20:28 ` Tom Lendacky
2024-01-12 20:37 ` Dave Hansen
2024-01-15 9:23 ` Vlastimil Babka
2024-01-16 16:19 ` Michael Roth
2024-01-16 16:50 ` Michael Roth
2024-01-16 20:12 ` Mike Rapoport
2024-01-26 1:49 ` Michael Roth
2024-01-16 18:22 ` Borislav Petkov
2024-01-16 20:22 ` Dave Hansen
2024-01-26 1:35 ` Michael Roth
2024-01-15 9:09 ` Borislav Petkov
2024-01-16 16:21 ` Dave Hansen
2024-01-17 9:34 ` Borislav Petkov
2024-01-15 9:01 ` Borislav Petkov
2023-12-30 16:19 ` [PATCH v1 12/26] crypto: ccp: Define the SEV-SNP commands Michael Roth
2024-01-15 9:41 ` Borislav Petkov
2024-01-26 1:56 ` Michael Roth
2023-12-30 16:19 ` [PATCH v1 13/26] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Michael Roth
2024-01-15 11:19 ` Borislav Petkov
2024-01-15 19:53 ` Borislav Petkov
2024-01-26 2:48 ` Michael Roth
2023-12-30 16:19 ` [PATCH v1 14/26] crypto: ccp: Provide API to issue SEV and SNP commands Michael Roth
2024-01-17 9:48 ` Borislav Petkov
2023-12-30 16:19 ` [PATCH v1 15/26] x86/sev: Introduce snp leaked pages list Michael Roth
2024-01-08 10:45 ` Vlastimil Babka
2024-01-09 22:19 ` Kalra, Ashish [this message]
2024-01-10 8:59 ` Vlastimil Babka
2023-12-30 16:19 ` [PATCH v1 16/26] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Michael Roth
2023-12-30 16:19 ` [PATCH v1 17/26] crypto: ccp: Handle non-volatile INIT_EX data " Michael Roth
2024-01-18 14:03 ` Borislav Petkov
2023-12-30 16:19 ` [PATCH v1 18/26] crypto: ccp: Handle legacy SEV commands " Michael Roth
2024-01-19 17:18 ` Borislav Petkov
2024-01-19 17:36 ` Tom Lendacky
2024-01-19 17:48 ` Borislav Petkov
2024-01-26 13:29 ` Michael Roth
2023-12-30 16:19 ` [PATCH v1 19/26] iommu/amd: Clean up RMP entries for IOMMU pages during SNP shutdown Michael Roth
2023-12-30 16:19 ` [PATCH v1 20/26] crypto: ccp: Add debug support for decrypting pages Michael Roth
2024-01-10 14:59 ` Sean Christopherson
2024-01-11 0:50 ` Michael Roth
2023-12-30 16:19 ` [PATCH v1 21/26] crypto: ccp: Add panic notifier for SEV/SNP firmware shutdown on kdump Michael Roth
2024-01-21 11:49 ` Borislav Petkov
2024-01-26 3:03 ` Kalra, Ashish
2024-01-26 13:38 ` Michael Roth
2023-12-30 16:19 ` [PATCH v1 22/26] KVM: SEV: Make AVIC backing, VMSA and VMCB memory allocation SNP safe Michael Roth
2024-01-21 11:51 ` Borislav Petkov
2024-01-26 3:44 ` Michael Roth
2023-12-30 16:19 ` [PATCH v1 23/26] x86/cpufeatures: Enable/unmask SEV-SNP CPU feature Michael Roth
2023-12-30 16:19 ` [PATCH v1 24/26] crypto: ccp: Add the SNP_PLATFORM_STATUS command Michael Roth
2024-01-21 12:29 ` Borislav Petkov
2024-01-26 3:32 ` Michael Roth
2023-12-30 16:19 ` [PATCH v1 25/26] crypto: ccp: Add the SNP_COMMIT command Michael Roth
2024-01-21 12:35 ` Borislav Petkov
2023-12-30 16:19 ` [PATCH v1 26/26] crypto: ccp: Add the SNP_SET_CONFIG command Michael Roth
2024-01-21 12:41 ` Borislav Petkov
2024-01-26 13:30 ` Michael Roth
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