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From: Sean Christopherson <seanjc@google.com>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, linux-coco@lists.linux.dev,
	linux-mm@kvack.org, linux-crypto@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	David Rientjes <rientjes@google.com>,
	Dov Murik <dovmurik@linux.ibm.com>,
	Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Borislav Petkov <bp@alien8.de>,
	Michael Roth <michael.roth@amd.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	"Kirill A . Shutemov" <kirill@shutemov.name>,
	Andi Kleen <ak@linux.intel.com>,
	tony.luck@intel.com, marcorr@google.com,
	sathyanarayanan.kuppuswamy@linux.intel.com
Subject: Re: [PATCH Part2 v5 37/45] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT
Date: Wed, 13 Oct 2021 17:24:43 +0000	[thread overview]
Message-ID: <YWcWW7eikkWSmCkH@google.com> (raw)
In-Reply-To: <a677423e-fa24-5b6a-785f-4cbdf0ebee37@amd.com>

On Wed, Oct 13, 2021, Brijesh Singh wrote:
> > The more I look at this, the more strongly I feel that private <=> shared conversions
> > belong in the MMU, and that KVM's SPTEs should be the single source of truth for
> > shared vs. private.  E.g. add a SPTE_TDP_PRIVATE_MASK in the software available bits.
> > I believe the only hiccup is the snafu where not zapping _all_ SPTEs on memslot
> > deletion breaks QEMU+VFIO+GPU, i.e. KVM would lose its canonical info on unrelated
> > memslot deletion.
> >
> > But that is a solvable problem.  Ideally the bug, wherever it is, would be root
> > caused and fixed.  I believe Peter (and Marc?) is going to work on reproducing
> > the bug.
> We have been also setting up VM with Qemu + VFIO + GPU usecase to repro
> the bug on AMD HW and so far we no luck in reproducing it. Will continue
> stressing the system to recreate it. Lets hope that Peter (and Marc) can
> easily recreate on Intel HW so that we can work towards fixing it.

Are you trying on a modern kernel?  If so, double check that nx_huge_pages is off,
turning that on caused the bug to disappear.  It should be off for AMD systems,
but it's worth checking.

> >> +		if (!rc) {
> >> +			/*
> >> +			 * This may happen if another vCPU unmapped the page
> >> +			 * before we acquire the lock. Retry the PSC.
> >> +			 */
> >> +			write_unlock(&kvm->mmu_lock);
> >> +			return 0;
> > How will the caller (guest?) know to retry the PSC if KVM returns "success"?
> 
> If a guest is adhering to the GHCB spec then it will see that hypervisor
> has not processed all the entry and it should retry the PSC.

But AFAICT that information isn't passed to the guest.  Even in this single-page
MSR-based case, the caller will say "all good" on a return of 0.

The "full" path is more obvious, as the caller clearly continues to process
entries unless there's an actual failure.

+       for (; cur <= end; cur++) {
+               entry = &info->entries[cur];
+               gpa = gfn_to_gpa(entry->gfn);
+               level = RMP_TO_X86_PG_LEVEL(entry->pagesize);
+               op = entry->operation;
+
+               if (!IS_ALIGNED(gpa, page_level_size(level))) {
+                       rc = PSC_INVALID_ENTRY;
+                       goto out;
+               }
+
+               rc = __snp_handle_page_state_change(vcpu, op, gpa, level);
+               if (rc)
+                       goto out;
+       }

  reply	other threads:[~2021-10-13 17:24 UTC|newest]

Thread overview: 239+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-20 15:58 [PATCH Part2 v5 00/45] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 01/45] x86/cpufeatures: Add SEV-SNP CPU feature Brijesh Singh
2021-09-16 16:56   ` Borislav Petkov
2021-09-16 17:35     ` Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 02/45] iommu/amd: Introduce function to check SEV-SNP support Brijesh Singh
2021-09-16 17:26   ` Borislav Petkov
2021-08-20 15:58 ` [PATCH Part2 v5 03/45] x86/sev: Add the host SEV-SNP initialization support Brijesh Singh
2021-09-24  8:58   ` Borislav Petkov
2021-08-20 15:58 ` [PATCH Part2 v5 04/45] x86/sev: Add RMP entry lookup helpers Brijesh Singh
2021-09-24  9:49   ` Borislav Petkov
2021-09-27 16:01     ` Brijesh Singh
2021-09-27 16:04       ` Brijesh Singh
2021-09-29 12:56         ` Borislav Petkov
2022-06-02 11:57   ` Jarkko Sakkinen
2021-08-20 15:58 ` [PATCH Part2 v5 05/45] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Brijesh Singh
2021-09-24 14:04   ` Borislav Petkov
2021-09-27 16:06     ` Brijesh Singh
2021-10-15 18:05   ` Sean Christopherson
2021-10-15 20:18     ` Brijesh Singh
2021-10-15 20:27       ` Sean Christopherson
2021-10-15 20:36         ` Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 06/45] x86/sev: Invalid pages from direct map when adding it to RMP table Brijesh Singh
2021-09-29 14:34   ` Borislav Petkov
2021-09-30 16:19     ` Brijesh Singh
2021-10-01 11:06       ` Borislav Petkov
2021-08-20 15:58 ` [PATCH Part2 v5 07/45] x86/traps: Define RMP violation #PF error code Brijesh Singh
2021-09-29 17:25   ` Borislav Petkov
2021-08-20 15:58 ` [PATCH Part2 v5 08/45] x86/fault: Add support to handle the RMP fault for user address Brijesh Singh
2021-08-23 14:20   ` Dave Hansen
2021-08-23 14:36     ` Brijesh Singh
2021-08-23 14:50       ` Dave Hansen
2021-08-24 16:42         ` Joerg Roedel
2021-08-25  9:16           ` Vlastimil Babka
2021-08-25 13:50             ` Tom Lendacky
2021-09-29 18:19   ` Borislav Petkov
2021-08-20 15:58 ` [PATCH Part2 v5 09/45] x86/fault: Add support to dump RMP entry on fault Brijesh Singh
2021-09-29 18:38   ` Borislav Petkov
2021-08-20 15:58 ` [PATCH Part2 v5 10/45] crypto: ccp: shutdown SEV firmware on kexec Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 11/45] crypto:ccp: Define the SEV-SNP commands Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 12/45] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 13/45] crypto:ccp: Provide APIs to issue SEV-SNP commands Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 14/45] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Brijesh Singh
2022-02-25 18:03   ` Alper Gun
2022-03-01 14:12     ` Brijesh Singh
2022-06-14  0:10   ` Alper Gun
2021-08-20 15:58 ` [PATCH Part2 v5 15/45] crypto: ccp: Handle the legacy SEV command " Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 16/45] crypto: ccp: Add the SNP_PLATFORM_STATUS command Brijesh Singh
2021-09-10  3:18   ` Marc Orr
2021-09-13 11:17     ` Brijesh Singh
2021-09-22 17:35   ` Dr. David Alan Gilbert
2021-09-23 18:01     ` Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 17/45] crypto: ccp: Add the SNP_{SET,GET}_EXT_CONFIG command Brijesh Singh
2021-09-01 21:02   ` Connor Kuehl
2021-09-01 23:06     ` Brijesh Singh
2021-09-10  3:27   ` Marc Orr
2021-09-13 11:29     ` Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 18/45] crypto: ccp: Provide APIs to query extended attestation report Brijesh Singh
2021-09-10  3:30   ` Marc Orr
2021-09-12  7:46     ` Dov Murik
2021-08-20 15:58 ` [PATCH Part2 v5 19/45] KVM: SVM: Add support to handle AP reset MSR protocol Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 20/45] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT Brijesh Singh
2021-10-12 20:38   ` Sean Christopherson
2021-08-20 15:58 ` [PATCH Part2 v5 21/45] KVM: SVM: Make AVIC backing, VMSA and VMCB memory allocation SNP safe Brijesh Singh
2021-09-22 18:55   ` Dr. David Alan Gilbert
2021-09-23 18:09     ` Brijesh Singh
2021-09-23 18:39       ` Dr. David Alan Gilbert
2021-09-23 22:23         ` Brijesh Singh
2021-09-23 19:17       ` Marc Orr
2021-09-23 20:44         ` Brijesh Singh
2021-09-23 20:55           ` Marc Orr
2021-10-12 20:44   ` Sean Christopherson
2021-08-20 15:58 ` [PATCH Part2 v5 22/45] KVM: SVM: Add initial SEV-SNP support Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 23/45] KVM: SVM: Add KVM_SNP_INIT command Brijesh Singh
2021-09-05  6:56   ` Dov Murik
2021-09-05 13:59     ` Brijesh Singh
2021-09-10  3:32   ` Marc Orr
2021-09-13 11:32     ` Brijesh Singh
2021-09-16 15:50   ` Peter Gonda
2022-06-13 20:58   ` Alper Gun
2022-06-13 23:15     ` Ashish Kalra
2022-06-13 23:33       ` Alper Gun
2022-06-14  0:21         ` Ashish Kalra
2022-06-14 15:37           ` Peter Gonda
2022-06-14 16:11             ` Kalra, Ashish
2022-06-14 16:30               ` Peter Gonda
2022-06-14 17:16                 ` Kalra, Ashish
2022-06-14 18:58                   ` Alper Gun
2022-06-14 20:23                     ` Kalra, Ashish
2022-06-14 20:29                       ` Peter Gonda
2022-06-14 20:39                         ` Kalra, Ashish
2021-08-20 15:58 ` [PATCH Part2 v5 24/45] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Brijesh Singh
2021-08-20 15:58 ` [PATCH Part2 v5 25/45] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Brijesh Singh
2021-09-27 16:43   ` Peter Gonda
2021-09-27 19:33     ` Brijesh Singh
2021-10-05 15:01       ` Peter Gonda
2021-08-20 15:58 ` [PATCH Part2 v5 26/45] KVM: SVM: Mark the private vma unmerable for SEV-SNP guests Brijesh Singh
2021-09-23 17:18   ` Dr. David Alan Gilbert
2021-10-12 18:46   ` Sean Christopherson
2021-10-13 12:39     ` Brijesh Singh
2021-10-13 14:34       ` Sean Christopherson
2021-10-13 14:51         ` Brijesh Singh
2021-10-13 15:33           ` Sean Christopherson
2021-08-20 15:59 ` [PATCH Part2 v5 27/45] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Brijesh Singh
2022-05-18 20:21   ` Marc Orr
2022-05-18 20:35     ` Kalra, Ashish
2021-08-20 15:59 ` [PATCH Part2 v5 28/45] KVM: X86: Keep the NPT and RMP page level in sync Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 29/45] KVM: x86/mmu: Move 'pfn' variable to caller of direct_page_fault() Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 30/45] KVM: x86/mmu: Introduce kvm_mmu_map_tdp_page() for use by TDX and SNP Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 31/45] KVM: x86: Introduce kvm_mmu_get_tdp_walk() for SEV-SNP use Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 32/45] KVM: x86: Define RMP page fault error bits for #NPF Brijesh Singh
2021-09-30 23:41   ` Marc Orr
2021-10-01 13:03     ` Borislav Petkov
2021-08-20 15:59 ` [PATCH Part2 v5 33/45] KVM: x86: Update page-fault trace to log full 64-bit error code Brijesh Singh
2021-10-13 21:23   ` Sean Christopherson
2021-08-20 15:59 ` [PATCH Part2 v5 34/45] KVM: SVM: Do not use long-lived GHCB map while setting scratch area Brijesh Singh
2021-10-13 21:20   ` Sean Christopherson
2021-10-15 16:11     ` Brijesh Singh
2021-10-15 16:44       ` Sean Christopherson
2021-08-20 15:59 ` [PATCH Part2 v5 35/45] KVM: SVM: Remove the long-lived GHCB host map Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 36/45] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 37/45] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Brijesh Singh
2021-09-28  9:56   ` Dr. David Alan Gilbert
2021-10-12 21:48   ` Sean Christopherson
2021-10-13 17:04     ` Sean Christopherson
2021-10-13 17:05     ` Brijesh Singh
2021-10-13 17:24       ` Sean Christopherson [this message]
2021-10-13 17:49         ` Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 38/45] KVM: SVM: Add support to handle " Brijesh Singh
2021-09-28 10:17   ` Dr. David Alan Gilbert
2021-09-28 23:20     ` Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 39/45] KVM: SVM: Introduce ops for the post gfn map and unmap Brijesh Singh
2021-10-13  0:23   ` Sean Christopherson
2021-10-13 18:10     ` Brijesh Singh
2021-10-13 20:10       ` Sean Christopherson
2021-10-13 21:49         ` Brijesh Singh
2021-10-13 22:10           ` Sean Christopherson
2021-10-13 22:31             ` Brijesh Singh
2021-10-13 20:16     ` Sean Christopherson
2021-10-15 16:31       ` Brijesh Singh
2021-10-15 17:16         ` Sean Christopherson
2022-09-08 21:21           ` Michael Roth
2022-09-08 22:28             ` Michael Roth
2022-09-14  8:05             ` Sean Christopherson
2022-09-14 11:02               ` Marc Orr
2022-09-14 16:15                 ` Sean Christopherson
2022-09-14 16:32                   ` Marc Orr
2022-09-14 16:39                     ` Marc Orr
2022-09-19 17:56               ` Michael Roth
2021-08-20 15:59 ` [PATCH Part2 v5 40/45] KVM: x86: Export the kvm_zap_gfn_range() for the SNP use Brijesh Singh
2021-08-20 15:59 ` [PATCH Part2 v5 41/45] KVM: SVM: Add support to handle the RMP nested page fault Brijesh Singh
2021-09-29 12:24   ` Dr. David Alan Gilbert
2021-10-13 17:57   ` Sean Christopherson
2021-08-20 15:59 ` [PATCH Part2 v5 42/45] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Brijesh Singh
2021-09-29 21:33   ` Peter Gonda
2021-09-29 22:00   ` Peter Gonda
2021-08-20 15:59 ` [PATCH Part2 v5 43/45] KVM: SVM: Use a VMSA physical address variable for populating VMCB Brijesh Singh
2021-10-15 18:58   ` Sean Christopherson
2021-08-20 15:59 ` [PATCH Part2 v5 44/45] KVM: SVM: Support SEV-SNP AP Creation NAE event Brijesh Singh
2021-10-15 19:50   ` Sean Christopherson
2021-10-20 21:48     ` Brijesh Singh
2021-10-20 23:01       ` Sean Christopherson
2021-08-20 15:59 ` [PATCH Part2 v5 45/45] KVM: SVM: Add module parameter to enable the SEV-SNP Brijesh Singh
2021-11-12 15:43 ` [PATCH Part2 v5 00/45] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Peter Gonda
2021-11-12 17:59   ` Dave Hansen
2021-11-12 18:35     ` Borislav Petkov
2021-11-12 19:48       ` Sean Christopherson
2021-11-12 20:04         ` Borislav Petkov
2021-11-12 20:37           ` Sean Christopherson
2021-11-12 20:53             ` Borislav Petkov
2021-11-12 21:12               ` Peter Gonda
2021-11-12 21:20                 ` Andy Lutomirski
2021-11-12 22:04                   ` Borislav Petkov
2021-11-12 22:52                   ` Peter Gonda
2021-11-13  0:00                 ` Sean Christopherson
2021-11-13  0:10                   ` Marc Orr
2021-11-13 18:34                     ` Sean Christopherson
2021-11-14  7:54                       ` Marc Orr
2021-11-15 17:16                         ` Sean Christopherson
2021-11-15 16:36                       ` Joerg Roedel
2021-11-15 17:25                         ` Sean Christopherson
2021-11-12 21:30             ` Marc Orr
2021-11-12 21:37               ` Dave Hansen
2021-11-12 21:40                 ` Marc Orr
2021-11-12 21:39               ` Andy Lutomirski
2021-11-12 21:43                 ` Marc Orr
2021-11-12 22:54                   ` Peter Gonda
2021-11-13  0:53                     ` Sean Christopherson
2021-11-13  1:04                       ` Marc Orr
2021-11-13 18:28                         ` Sean Christopherson
2021-11-14  7:41                           ` Marc Orr
2021-11-15 18:17                             ` Sean Christopherson
2021-11-15 16:52                           ` Joerg Roedel
2021-11-15 16:18             ` Brijesh Singh
2021-11-15 18:44               ` Sean Christopherson
2021-11-15 18:58                 ` Brijesh Singh
2021-11-12 21:16         ` Marc Orr
2021-11-12 21:23           ` Andy Lutomirski
2021-11-12 21:35             ` Borislav Petkov
2021-11-15 12:30         ` Dr. David Alan Gilbert
2021-11-15 14:42           ` Joerg Roedel
2021-11-15 15:33             ` Dr. David Alan Gilbert
2021-11-15 16:20               ` Joerg Roedel
2021-11-15 16:32                 ` Dr. David Alan Gilbert
2021-11-15 18:26           ` Sean Christopherson
2021-11-15 18:41             ` Marc Orr
2021-11-15 19:15               ` Sean Christopherson
2021-11-16  3:07                 ` Marc Orr
2021-11-16  5:14                   ` Andy Lutomirski
2021-11-16 13:21                     ` Joerg Roedel
2021-11-16 18:26                       ` Sean Christopherson
2021-11-16 18:39                         ` Peter Gonda
2021-11-16 13:30                 ` Joerg Roedel
2021-11-16  5:00               ` Andy Lutomirski
2021-11-16 13:02             ` Joerg Roedel
2021-11-16 20:08               ` Sean Christopherson
2021-11-15 16:16         ` Joerg Roedel
2021-11-22 15:23   ` Brijesh Singh
2021-11-22 17:03     ` Vlastimil Babka
2021-11-22 18:01       ` Brijesh Singh
2021-11-22 18:30     ` Dave Hansen
2021-11-22 19:06       ` Brijesh Singh
2021-11-22 19:14         ` Dave Hansen
2021-11-22 20:33           ` Brijesh Singh
2021-11-22 21:34             ` Sean Christopherson
2021-11-22 22:51             ` Dave Hansen
2021-11-23  5:15               ` Luck, Tony
2021-11-23  7:18               ` Borislav Petkov
2021-11-23 15:36                 ` Sean Christopherson
2021-11-23 16:26                   ` Borislav Petkov
2021-11-23  8:55               ` Vlastimil Babka
2021-11-24 16:03               ` Joerg Roedel
2021-11-24 17:48                 ` Dave Hansen
2021-11-24 19:34                   ` Vlastimil Babka
2021-11-25 10:05                   ` Joerg Roedel
2021-11-29 14:44                     ` Brijesh Singh
2021-11-29 14:58                       ` Vlastimil Babka
2021-11-29 16:13                         ` Brijesh Singh
2021-11-30 19:40                           ` Vlastimil Babka
2021-11-29 16:41                     ` Dave Hansen

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