From: Vlastimil Babka <vbabka@suse.cz>
To: Michael Roth <michael.roth@amd.com>, kvm@vger.kernel.org
Cc: linux-coco@lists.linux.dev, linux-mm@kvack.org,
linux-crypto@vger.kernel.org, x86@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,
dovmurik@linux.ibm.com, tobin@ibm.com, bp@alien8.de,
kirill@shutemov.name, ak@linux.intel.com, tony.luck@intel.com,
marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com,
alpergun@google.com, dgilbert@redhat.com, jarkko@kernel.org,
ashish.kalra@amd.com, nikunj.dadhania@amd.com,
Brijesh Singh <brijesh.singh@amd.com>,
Jarkko Sakkinen <jarkko.sakkinen@profian.com>
Subject: Re: [PATCH RFC v8 17/56] x86/fault: Add support to handle the RMP fault for user address
Date: Fri, 3 Mar 2023 16:31:59 +0100 [thread overview]
Message-ID: <846ff1ae-ba1e-8c57-f727-511c09ac0807@suse.cz> (raw)
In-Reply-To: <20230220183847.59159-18-michael.roth@amd.com>
On 2/20/23 19:38, Michael Roth wrote:
> +static int handle_user_rmp_page_fault(struct pt_regs *regs, unsigned long error_code,
> + unsigned long address)
> +{
> + int rmp_level, level;
> + pgd_t *pgd;
> + pte_t *pte;
> + u64 pfn;
> +
> + pgd = __va(read_cr3_pa());
> + pgd += pgd_index(address);
> +
> + pte = lookup_address_in_pgd(pgd, address, &level);
> +
> + /*
> + * It can happen if there was a race between an unmap event and
> + * the RMP fault delivery.
> + */
> + if (!pte || !pte_present(*pte))
> + return RMP_PF_UNMAP;
> +
> + /*
> + * RMP page fault handler follows this algorithm:
> + * 1. Compute the pfn for the 4kb page being accessed
> + * 2. Read that RMP entry -- If it is assigned then kill the process
> + * 3. Otherwise, check the level from the host page table
> + * If level=PG_LEVEL_4K then the page is already smashed
> + * so just retry the instruction
> + * 4. If level=PG_LEVEL_2M/1G, then the host page needs to be split
> + */
> +
> + pfn = pte_pfn(*pte);
> +
> + /* If its large page then calculte the fault pfn */
> + if (level > PG_LEVEL_4K)
> + pfn = pfn | PFN_DOWN(address & (page_level_size(level) - 1));
> +
> + /*
> + * If its a guest private page, then the fault cannot be resolved.
> + * Send a SIGBUS to terminate the process.
> + *
> + * As documented in APM vol3 pseudo-code for RMPUPDATE, when the 2M range
> + * is covered by a valid (Assigned=1) 2M entry, the middle 511 4k entries
> + * also have Assigned=1. This means that if there is an access to a page
> + * which happens to lie within an Assigned 2M entry, the 4k RMP entry
> + * will also have Assigned=1. Therefore, the kernel should see that
> + * the page is not a valid page and the fault cannot be resolved.
> + */
> + if (snp_lookup_rmpentry(pfn, &rmp_level)) {
> + pr_info("Fatal RMP page fault, terminating process, entry assigned for pfn 0x%llx\n",
> + pfn);
> + do_sigbus(regs, error_code, address, VM_FAULT_SIGBUS);
> + return RMP_PF_RETRY;
> + }
WRT my reply to 12/56, for example here it might be useful to distinguish
the rmp being assigned from an error of snp_lookup_rmpentry()?
> +
> + /*
> + * The backing page level is higher than the RMP page level, request
> + * to split the page.
> + */
> + if (level > rmp_level)
> + return RMP_PF_SPLIT;
> +
> + return RMP_PF_RETRY;
> +}
> +
> /*
next prev parent reply other threads:[~2023-03-03 15:32 UTC|newest]
Thread overview: 147+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-20 18:37 [PATCH RFC v8 00/56] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 01/56] KVM: x86: Add 'fault_is_private' x86 op Michael Roth
2023-03-01 10:25 ` Zhi Wang
2023-03-18 4:51 ` Isaku Yamahata
2023-03-20 17:46 ` Michael Roth
2023-03-18 4:53 ` Isaku Yamahata
2023-02-20 18:37 ` [PATCH RFC v8 02/56] KVM: x86: Add 'update_mem_attr' " Michael Roth
2023-03-18 4:56 ` Isaku Yamahata
2023-03-20 18:05 ` Michael Roth
2023-03-21 11:21 ` Zhi Wang
2023-03-22 1:58 ` Michael Roth
2023-03-23 18:17 ` Zhi Wang
2023-03-28 4:36 ` Michael Roth
2023-03-28 23:00 ` Zhi Wang
2023-03-29 23:50 ` Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 03/56] KVM: x86: Add platform hooks for private memory invalidations Michael Roth
2023-03-18 5:13 ` Isaku Yamahata
2023-03-20 18:09 ` Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 04/56] KVM: Add HVA range operator Michael Roth
2023-02-20 21:37 ` Zhi Wang
2023-03-27 0:34 ` Michael Roth
2023-04-04 14:40 ` Zhi Wang
2023-02-20 18:37 ` [PATCH RFC v8 05/56] KVM: SEV: Require KVM_PROTECTED_VM when AMD_MEM_ENCRYPT is enabled Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 06/56] KVM: Split out memory attribute xarray updates to helper function Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 07/56] KVM: SEV: Populate private memory fd during LAUNCH_UPDATE_DATA Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 08/56] KVM: SEV: Rename sev_{pin,unpin}_memory Michael Roth
2023-03-03 14:00 ` Vlastimil Babka
2023-03-06 11:01 ` Nikunj A. Dadhania
2023-02-20 18:38 ` [PATCH RFC v8 09/56] KVM: SEV: Handle memory backed by restricted memfd Michael Roth
2023-03-03 14:05 ` Vlastimil Babka
2023-03-06 11:03 ` Nikunj A. Dadhania
2023-02-20 18:38 ` [PATCH RFC v8 10/56] x86/cpufeatures: Add SEV-SNP CPU feature Michael Roth
2023-02-21 21:21 ` Sathyanarayanan Kuppuswamy
2023-02-22 23:27 ` Kalra, Ashish
2023-02-20 18:38 ` [PATCH RFC v8 11/56] x86/sev: Add the host SEV-SNP initialization support Michael Roth
2023-02-20 20:12 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 12/56] x86/sev: Add RMP entry lookup helpers Michael Roth
2023-03-03 15:28 ` Vlastimil Babka
2023-03-29 22:59 ` Michael Roth
2023-04-20 16:31 ` Vlastimil Babka
2023-02-20 18:38 ` [PATCH RFC v8 13/56] x86/fault: Add helper for dumping RMP entries Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 14/56] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 15/56] x86/sev: Invalidate pages from the direct map when adding them to the RMP table Michael Roth
2023-03-01 12:07 ` Tom Dohrmann
2023-03-01 16:15 ` Dave Hansen
2023-03-28 22:12 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 16/56] x86/traps: Define RMP violation #PF error code Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 17/56] x86/fault: Add support to handle the RMP fault for user address Michael Roth
2023-03-01 16:21 ` Dave Hansen
2023-03-28 23:31 ` Michael Roth
2023-04-11 18:27 ` Dave Hansen
2023-03-03 15:31 ` Vlastimil Babka [this message]
2023-02-20 18:38 ` [PATCH RFC v8 18/56] x86/fault: fix handle_split_page_fault() to work with memfd backed pages Michael Roth
2023-02-20 19:57 ` Hugh Dickins
2023-02-20 20:31 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 19/56] x86/fault: Return pfn from dump_pagetable() for SEV-specific fault handling Michael Roth
2023-02-20 21:13 ` Zhi Wang
2023-02-28 10:53 ` Wu Zongyong
2023-02-20 18:38 ` [PATCH RFC v8 20/56] crypto:ccp: Define the SEV-SNP commands Michael Roth
2023-04-17 14:54 ` Sabin Rapan
2023-02-20 18:38 ` [PATCH RFC v8 21/56] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 22/56] crypto:ccp: Provide API to issue SEV and SNP commands Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 23/56] crypto: ccp: Introduce snp leaked pages list Michael Roth
2023-03-03 15:54 ` Vlastimil Babka
2023-02-20 18:38 ` [PATCH RFC v8 24/56] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Michael Roth
2023-02-21 9:28 ` Zhi Wang
2023-02-21 15:31 ` Kalra, Ashish
2023-02-21 21:15 ` Zhi Wang
2023-02-21 22:06 ` Kalra, Ashish
2023-02-20 18:38 ` [PATCH RFC v8 25/56] crypto: ccp: Handle the legacy SEV command " Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 26/56] crypto: ccp: Add the SNP_PLATFORM_STATUS command Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 27/56] crypto: ccp: Add the SNP_{SET,GET}_EXT_CONFIG command Michael Roth
2023-02-22 12:32 ` Zhi Wang
2023-02-22 16:50 ` Tom Lendacky
2023-02-22 22:43 ` Kalra, Ashish
2023-02-23 6:38 ` Zhi Wang
2023-02-23 14:19 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 28/56] crypto: ccp: Provide APIs to query extended attestation report Michael Roth
2023-02-22 20:24 ` Zhi Wang
2023-02-22 22:35 ` Kalra, Ashish
2023-02-23 8:14 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 29/56] KVM: SVM: Add support to handle AP reset MSR protocol Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 30/56] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 31/56] KVM: SVM: Make AVIC backing, VMSA and VMCB memory allocation SNP safe Michael Roth
2023-02-22 20:42 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 32/56] KVM: SVM: Add initial SEV-SNP support Michael Roth
2023-02-23 17:46 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 33/56] KVM: SVM: Add KVM_SNP_INIT command Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 34/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2023-02-23 21:41 ` Zhi Wang
2023-02-24 16:22 ` Tom Lendacky
2023-04-26 17:06 ` Sabin Rapan
2023-04-26 18:02 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 35/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2023-02-24 11:55 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 36/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2023-03-24 14:40 ` Alexander Graf
2023-02-20 18:38 ` [PATCH RFC v8 37/56] KVM: X86: Keep the NPT and RMP page level in sync Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 38/56] KVM: x86: Define RMP page fault error bits for #NPF Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 39/56] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 40/56] KVM: SVM: Add KVM_EXIT_VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 41/56] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2023-02-24 15:06 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 42/56] KVM: SVM: Add support to handle " Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 43/56] KVM: x86: Export the kvm_zap_gfn_range() for the SNP use Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 44/56] KVM: SVM: Add support to handle the RMP nested page fault Michael Roth
2023-02-28 19:11 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 45/56] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2023-02-24 11:01 ` Alexander Graf
2023-02-28 19:34 ` Zhi Wang
2023-04-17 13:05 ` Alexander Graf
2023-02-20 18:38 ` [PATCH RFC v8 46/56] KVM: SVM: Use a VMSA physical address variable for populating VMCB Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 47/56] KVM: SVM: Support SEV-SNP AP Creation NAE event Michael Roth
2023-02-24 12:37 ` Alexander Graf
2023-02-28 20:47 ` Zhi Wang
2023-03-01 21:14 ` Alexander Graf
2023-04-05 0:54 ` Michael Roth
2023-04-04 22:48 ` Michael Roth
2023-04-05 15:20 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 48/56] KVM: SVM: Add SNP-specific handling for memory attribute updates Michael Roth
2023-03-01 23:37 ` Dave Hansen
2023-04-05 23:48 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 49/56] KVM: SVM: Implement .fault_is_private callback for SNP Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 50/56] KVM: SEV: Handle restricted memory invalidations " Michael Roth
2023-03-01 10:41 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 51/56] KVM: SVM: Add module parameter to enable the SEV-SNP Michael Roth
2023-03-01 10:45 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 52/56] ccp: Add support to decrypt the page Michael Roth
2023-03-01 21:20 ` Zhi Wang
2023-03-02 5:59 ` Dov Murik
2023-03-02 14:33 ` Tom Lendacky
2023-03-02 21:11 ` Dov Murik
2023-02-20 18:38 ` [PATCH RFC v8 53/56] KVM: SVM: Make VMSAVE target area memory allocation SNP safe Michael Roth
2023-03-01 21:23 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 54/56] x86/sev: Add KVM commands for instance certs Michael Roth
2023-02-21 12:40 ` Dov Murik
2023-03-02 0:02 ` Zhi Wang
2023-03-02 1:41 ` Dionna Amalie Glaze
2023-03-02 11:27 ` Zhi Wang
2023-03-02 11:34 ` Dov Murik
2023-02-20 18:38 ` [PATCH RFC v8 55/56] x86/sev: Document KVM_SEV_SNP_{G,S}ET_CERTS Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 56/56] iommu/amd: Add IOMMU_SNP_SHUTDOWN support Michael Roth
2023-03-01 16:56 ` [PATCH RFC v8 00/56] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Dave Hansen
2023-03-01 22:59 ` Zhi Wang
2023-03-01 23:39 ` Dave Hansen
2023-08-03 18:27 ` Schander, Johanna 'Mimoja' Amelie
2023-08-04 1:01 ` Kalra, Ashish
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