From: Michael Roth <michael.roth@amd.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: <kvm@vger.kernel.org>, <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>,
<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>,
<vbabka@suse.cz>, <kirill@shutemov.name>, <ak@linux.intel.com>,
<tony.luck@intel.com>,
<sathyanarayanan.kuppuswamy@linux.intel.com>,
<alpergun@google.com>, <jarkko@kernel.org>,
<ashish.kalra@amd.com>, <nikunj.dadhania@amd.com>,
<pankaj.gupta@amd.com>, <liam.merwick@oracle.com>
Subject: Re: [PATCH v12 22/29] KVM: SEV: Implement gmem hook for invalidating private pages
Date: Thu, 18 Apr 2024 14:57:54 -0500 [thread overview]
Message-ID: <20240418195754.h6gl5qd62kas7crx@amd.com> (raw)
In-Reply-To: <f1e5aef5-989c-4f07-82af-9ed54cc192be@redhat.com>
On Sat, Mar 30, 2024 at 10:31:47PM +0100, Paolo Bonzini wrote:
> On 3/29/24 23:58, Michael Roth wrote:
> > + /*
> > + * If an unaligned PFN corresponds to a 2M region assigned as a
> > + * large page in he RMP table, PSMASH the region into individual
> > + * 4K RMP entries before attempting to convert a 4K sub-page.
> > + */
> > + if (!use_2m_update && rmp_level > PG_LEVEL_4K) {
> > + rc = snp_rmptable_psmash(pfn);
> > + if (rc)
> > + pr_err_ratelimited("SEV: Failed to PSMASH RMP entry for PFN 0x%llx error %d\n",
> > + pfn, rc);
> > + }
>
> Ignoring the PSMASH failure is pretty scary... At this point .free_folio
> cannot fail, should the psmash part of this patch be done in
> kvm_gmem_invalidate_begin() before kvm_mmu_unmap_gfn_range()?
>
> Also, can you get PSMASH_FAIL_INUSE and if so what's the best way to address
> it? Should fallocate() return -EBUSY?
FAIL_INUSE shouldn't occur since at this point the pages have been unmapped
from NPT and only the task doing the cleanup should be attempting to
access/PSMASH this particular 2M HPA range at this point.
However, since FAIL_INUSE is transient, there isn't a good reason why we
shouldn't retry until it clears itself up rather than risk hosing the
system if some unexpected case ever did pop up, so I've updated
snp_rmptable_psmash() to handle that case automatically and simplify the
handling in sev_handle_rmp_fault() as well. (in the case of #NPF RMP
faults there is actually potential for PSMASH errors other than
FAIL_INUSE due to races with other vCPU threads which can interleave and
put the RMP entry in an unexpected state, so there's additional
handling/reporting to deal with those cases, but here they are not expected
and will trigger WARN_*ONCE()'s now)
I used this hacked up version of Sean's original patch to re-enable 2MB
hugepage support in gmem for the purposes of re-testing this:
https://github.com/mdroth/linux/commit/15aa4f81811485997953130fc184e829ba4399d2
-Mike
>
> Thanks,
>
> Paolo
>
>
next prev parent reply other threads:[~2024-04-18 20:03 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-29 22:58 [PATCH v12 00/29] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 01/29] [TEMP] x86/kvm/Kconfig: Have KVM_AMD_SEV select ARCH_HAS_CC_PLATFORM Michael Roth
2024-03-29 22:58 ` [PATCH v12 02/29] [TEMP] x86/cc: Add cc_platform_set/_clear() helpers Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 03/29] [TEMP] x86/CPU/AMD: Track SNP host status with cc_platform_*() Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 04/29] [TEMP] fixup! KVM: SEV: sync FPU and AVX state at LAUNCH_UPDATE_VMSA time Michael Roth
2024-03-29 22:58 ` [PATCH v12 05/29] KVM: x86: Define RMP page fault error bits for #NPF Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 19:28 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 06/29] KVM: SEV: Select KVM_GENERIC_PRIVATE_MEM when CONFIG_KVM_AMD_SEV=y Michael Roth
2024-03-29 22:58 ` [PATCH v12 07/29] KVM: SEV: Add support to handle AP reset MSR protocol Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 08/29] KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 09/29] KVM: SEV: Add initial SEV-SNP support Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 19:58 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 10/29] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 20:20 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 11/29] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 20:31 ` Paolo Bonzini
2024-04-01 22:22 ` Michael Roth
2024-04-02 22:58 ` Isaku Yamahata
2024-04-03 12:51 ` Paolo Bonzini
2024-04-03 15:37 ` Isaku Yamahata
2024-04-04 16:03 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 12/29] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 20:41 ` Paolo Bonzini
2024-04-01 23:17 ` Michael Roth
2024-04-03 12:56 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 13/29] KVM: SEV: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 14/29] KVM: SEV: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2024-03-29 22:58 ` [PATCH v12 15/29] KVM: SEV: Add support to handle " Michael Roth
2024-03-29 22:58 ` [PATCH v12 16/29] KVM: x86: Export the kvm_zap_gfn_range() for the SNP use Michael Roth
2024-03-30 20:51 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 17/29] KVM: SEV: Add support to handle RMP nested page faults Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 20:55 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 18/29] KVM: SEV: Use a VMSA physical address variable for populating VMCB Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 21:01 ` Paolo Bonzini
2024-04-16 11:53 ` Paolo Bonzini
2024-04-16 14:25 ` Tom Lendacky
2024-04-16 17:00 ` Paolo Bonzini
2024-04-17 20:57 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 19/29] KVM: SEV: Support SEV-SNP AP Creation NAE event Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 20/29] KVM: SEV: Add support for GHCB-based termination requests Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` [PATCH v12 21/29] KVM: SEV: Implement gmem hook for initializing private pages Michael Roth
2024-03-30 21:05 ` Paolo Bonzini
2024-03-30 21:05 ` Paolo Bonzini
2024-03-30 21:05 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 22/29] KVM: SEV: Implement gmem hook for invalidating " Michael Roth
2024-03-30 21:31 ` Paolo Bonzini
2024-03-30 21:31 ` Paolo Bonzini
2024-03-30 21:31 ` Paolo Bonzini
2024-04-18 19:57 ` Michael Roth [this message]
2024-03-29 22:58 ` [PATCH v12 23/29] KVM: x86: Implement gmem hook for determining max NPT mapping level Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-30 21:35 ` Paolo Bonzini
2024-03-30 21:35 ` Paolo Bonzini
2024-03-30 21:35 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 24/29] KVM: SEV: Avoid WBINVD for HVA-based MMU notifications for SNP Michael Roth
2024-03-30 21:35 ` Paolo Bonzini
2024-03-30 21:35 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 25/29] KVM: SVM: Add module parameter to enable the SEV-SNP Michael Roth
2024-03-30 21:35 ` Paolo Bonzini
2024-03-30 21:35 ` Paolo Bonzini
2024-03-29 22:58 ` [PATCH v12 26/29] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-04-10 22:14 ` Tom Lendacky
2024-03-29 22:58 ` [PATCH v12 27/29] crypto: ccp: Add the SNP_VLEK_LOAD command Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-04-10 22:20 ` Tom Lendacky
2024-03-29 22:58 ` [PATCH v12 28/29] crypto: ccp: Add the SNP_{PAUSE,RESUME}_ATTESTATION commands Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-04-10 22:27 ` Tom Lendacky
2024-03-29 22:58 ` [PATCH v12 29/29] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event Michael Roth
2024-03-29 22:58 ` Michael Roth
2024-04-11 13:33 ` Tom Lendacky
2024-03-30 21:44 ` [PATCH v12 00/29] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Paolo Bonzini
2024-03-30 21:44 ` Paolo Bonzini
2024-03-30 21:44 ` Paolo Bonzini
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