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From: Peter Gonda <pgonda@google.com>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	kvm list <kvm@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	jroedel@suse.de, "Lendacky, Thomas" <thomas.lendacky@amd.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Ingo Molnar <mingo@redhat.com>,
	Dave Hansen <dave.hansen@intel.com>,
	David Rientjes <rientjes@google.com>,
	Sean Christopherson <seanjc@google.com>,
	peterz@infradead.org, "H. Peter Anvin" <hpa@zytor.com>,
	tony.luck@intel.com
Subject: Re: [PATCH Part2 RFC v2 32/37] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT
Date: Mon, 10 May 2021 13:59:08 -0600	[thread overview]
Message-ID: <CAMkAt6rfnjqPZHUqJM1r6GjnBMy-Gbw8VtGv4gd-G0Rjq+ALnQ@mail.gmail.com> (raw)
In-Reply-To: <84f52e0e-b034-ebcf-e787-7ef9e3baae2f@amd.com>

On Mon, May 10, 2021 at 11:51 AM Brijesh Singh <brijesh.singh@amd.com> wrote:
>
> Hi Peter,
>
> On 5/10/21 12:30 PM, Peter Gonda wrote:
> >> +static int snp_make_page_shared(struct kvm_vcpu *vcpu, gpa_t gpa, kvm_pfn_t pfn, int level)
> >> +{
> >> +       struct rmpupdate val;
> >> +       int rc, rmp_level;
> >> +       struct rmpentry *e;
> >> +
> >> +       e = snp_lookup_page_in_rmptable(pfn_to_page(pfn), &rmp_level);
> >> +       if (!e)
> >> +               return -EINVAL;
> >> +
> >> +       if (!rmpentry_assigned(e))
> >> +               return 0;
> >> +
> >> +       /* Log if the entry is validated */
> >> +       if (rmpentry_validated(e))
> >> +               pr_debug_ratelimited("Remove RMP entry for a validated gpa 0x%llx\n", gpa);
> >> +
> >> +       /*
> >> +        * Is the page part of an existing 2M RMP entry ? Split the 2MB into multiple
> >> +        * of 4K-page before making the memory shared.
> >> +        */
> >> +       if ((level == PG_LEVEL_4K) && (rmp_level == PG_LEVEL_2M)) {
> >> +               rc = snp_rmptable_psmash(vcpu, pfn);
> >> +               if (rc)
> >> +                       return rc;
> >> +       }
> >> +
> >> +       memset(&val, 0, sizeof(val));
> >> +       val.pagesize = X86_TO_RMP_PG_LEVEL(level);
> > This is slightly different from Rev 2.00 of the GHCB spec. This
> > defaults to 2MB page sizes, when the spec says the only valid settings
> > for level are 0 -> 4k pages or 1 -> 2MB pages. Should this enforce the
> > same strictness as the spec?
>
>
> The caller of the snp_make_page_shared() must pass the x86 page level.
> We should reach here after all the guest provide value have passed
> through checks.
>
> The call sequence in this case should be:
>
> snp_handle_vmgexit_msr_protocol()
>
>  __snp_handle_page_state_change(vcpu, gfn_to_gpa(gfn), PG_LEVEL_4K)
>
>   snp_make_page_shared(..., level)
>
> Am I missing something  ?

Thanks Brijesh. I think my comment was misplaced. Looking at 33/37

+static unsigned long snp_handle_page_state_change(struct vcpu_svm
*svm, struct ghcb *ghcb)
+{
...
+ while (info->header.cur_entry <= info->header.end_entry) {
+ entry = &info->entry[info->header.cur_entry];
+ gpa = gfn_to_gpa(entry->gfn);
+ level = RMP_TO_X86_PG_LEVEL(entry->pagesize);
+ op = entry->operation;

This call to RMP_TO_X86_PG_LEVEL is not as strict as the spec. Is that OK?

>
> >> +       return rmpupdate(pfn_to_page(pfn), &val);
> >> +}
> >> +
> >> +static int snp_make_page_private(struct kvm_vcpu *vcpu, gpa_t gpa, kvm_pfn_t pfn, int level)
> >> +{
> >> +       struct kvm_sev_info *sev = &to_kvm_svm(vcpu->kvm)->sev_info;
> >> +       struct rmpupdate val;
> >> +       struct rmpentry *e;
> >> +       int rmp_level;
> >> +
> >> +       e = snp_lookup_page_in_rmptable(pfn_to_page(pfn), &rmp_level);
> >> +       if (!e)
> >> +               return -EINVAL;
> >> +
> >> +       /* Log if the entry is validated */
> >> +       if (rmpentry_validated(e))
> >> +               pr_err_ratelimited("Asked to make a pre-validated gpa %llx private\n", gpa);
> >> +
> >> +       memset(&val, 0, sizeof(val));
> >> +       val.gpa = gpa;
> >> +       val.asid = sev->asid;
> >> +       val.pagesize = X86_TO_RMP_PG_LEVEL(level);
> > Same comment as above.
>
> See my above response.
>
>
> >
> >> +       val.assigned = true;
> >> +
> >> +       return rmpupdate(pfn_to_page(pfn), &val);
> >> +}

  reply	other threads:[~2021-05-10 19:59 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-30 12:37 [PATCH Part2 RFC v2 00/37] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 01/37] KVM: SVM: Add support to handle AP reset MSR protocol Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 02/37] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 03/37] KVM: SVM: Increase the GHCB protocol version Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 04/37] x86/cpufeatures: Add SEV-SNP CPU feature Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 05/37] x86/sev: Add the host SEV-SNP initialization support Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 06/37] x86/sev: Add RMP entry lookup helpers Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 07/37] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 08/37] x86/sev: Split the physmap when adding the page in RMP table Brijesh Singh
2021-05-03 15:07   ` Peter Zijlstra
2021-05-03 15:15   ` Andy Lutomirski
2021-05-03 15:41     ` Dave Hansen
2021-05-07 11:28       ` Vlastimil Babka
2021-04-30 12:37 ` [PATCH Part2 RFC v2 09/37] x86/traps: Define RMP violation #PF error code Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 10/37] x86/fault: Add support to handle the RMP fault for kernel address Brijesh Singh
2021-05-03 14:44   ` Dave Hansen
2021-05-03 15:03     ` Andy Lutomirski
2021-05-03 15:49       ` Brijesh Singh
2021-05-03 15:37     ` Brijesh Singh
2021-05-03 16:15       ` Dave Hansen
2021-05-03 17:19         ` Brijesh Singh
2021-05-03 17:31           ` Brijesh Singh
2021-05-03 17:40           ` Andy Lutomirski
2021-05-03 19:41             ` Brijesh Singh
2021-05-03 19:43               ` Dave Hansen
2021-05-04 12:31                 ` Brijesh Singh
2021-05-04 14:33                   ` Dave Hansen
2021-05-04 15:16                     ` Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 11/37] x86/fault: Add support to handle the RMP fault for user address Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 12/37] crypto:ccp: Define the SEV-SNP commands Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 13/37] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Brijesh Singh
2021-04-30 12:37 ` [PATCH Part2 RFC v2 14/37] crypto: ccp: Shutdown SNP firmware on kexec Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 15/37] crypto:ccp: Provide APIs to issue SEV-SNP commands Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 16/37] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Brijesh Singh
2021-05-10 18:23   ` Peter Gonda
2021-05-10 20:07     ` Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 17/37] crypto: ccp: Handle the legacy SEV command " Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 18/37] KVM: SVM: make AVIC backing, VMSA and VMCB memory allocation SNP safe Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 19/37] KVM: SVM: Add initial SEV-SNP support Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 20/37] KVM: SVM: define new SEV_FEATURES field in the VMCB Save State Area Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 21/37] KVM: SVM: Add KVM_SNP_INIT command Brijesh Singh
2021-05-06 20:25   ` Peter Gonda
2021-05-06 22:29     ` Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 22/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 23/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 24/37] KVM: SVM: Reclaim the guest pages when SEV-SNP VM terminates Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 25/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 26/37] KVM: X86: Add kvm_x86_ops to get the max page level for the TDP Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 27/37] KVM: X86: Introduce kvm_mmu_map_tdp_page() for use by SEV Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 28/37] KVM: X86: Introduce kvm_mmu_get_tdp_walk() for SEV-SNP use Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 29/37] KVM: X86: Define new RMP check related #NPF error bits Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 30/37] KVM: X86: update page-fault trace to log the 64-bit error code Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 31/37] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 32/37] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Brijesh Singh
2021-05-10 17:30   ` Peter Gonda
2021-05-10 17:51     ` Brijesh Singh
2021-05-10 19:59       ` Peter Gonda [this message]
2021-05-10 20:50         ` Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 33/37] KVM: SVM: Add support to handle " Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 34/37] KVM: X86: Export the kvm_zap_gfn_range() for the SNP use Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 35/37] KVM: SVM: Add support to handle the RMP nested page fault Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 36/37] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Brijesh Singh
2021-05-10 18:57   ` Peter Gonda
2021-05-10 20:14     ` Brijesh Singh
2021-05-10 21:17       ` Sean Christopherson
2021-05-11 18:34         ` Brijesh Singh
2021-04-30 12:38 ` [PATCH Part2 RFC v2 37/37] KVM: SVM: Advertise the SEV-SNP feature support Brijesh Singh

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