From: Paolo Bonzini <pbonzini@redhat.com>
To: "Huang, Kai" <kai.huang@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "amit.shah@amd.com" <amit.shah@amd.com>,
"Kohler, Jon" <jon@nutanix.com>,
"seanjc@google.com" <seanjc@google.com>,
"mtosatti@redhat.com" <mtosatti@redhat.com>,
"nikunj@amd.com" <nikunj@amd.com>
Subject: Re: [PATCH 03/22] KVM: x86/mmu: adjust MMIO generation bit allocation and allowed mask
Date: Tue, 24 Mar 2026 10:11:42 +0100 [thread overview]
Message-ID: <bedeb0c3-abbf-4466-85a8-9e62c2488451@redhat.com> (raw)
In-Reply-To: <0bd8c0720a618b15ccf7e76a4b34e89eb4315c00.camel@intel.com>
On 3/24/26 04:48, Huang, Kai wrote:
>
>> /*
>> - * Due to limited space in PTEs, the MMIO generation is a 19 bit subset of
>> + * Due to limited space in PTEs, the MMIO generation is an 18 bit subset of
>> * the memslots generation and is derived as follows:
>
> Is "a -> an" unintentional change?
No, "a nineteen-bit" -> "an eighteen-bit". :)
> Besides the changes to MMIO_GEN, the FROZEN_SPTE seems to have bit 10 set:
>
> #define FROZEN_SPTE (SHADOW_NONPRESENT_VALUE | 0x5a0ULL)
>
> When MBEC is enabled, IIUC such SPTE will be treated as present by hardware
> if CPU supports execution-only SPTE.
>
> Also, when MBEC is enabled, per SDM if CPU doesn't support execution-only,
> an SPTE with bit 0 clear but with bit 10 set will trigger EPT
> miscofiguration, rather than EPT violation.
>
> So seems we should exclude bit 10 from FROZEN_SPTE.
True, good catch (so 0x5a0 should become 0x1a0).
Paolo
next prev parent reply other threads:[~2026-03-24 9:11 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-21 0:09 [RFC PATCH 00/22] KVM: combined patchset for MBEC/GMET support Paolo Bonzini
2026-03-21 0:09 ` [PATCH 01/22] KVM: TDX/VMX: rework EPT_VIOLATION_EXEC_FOR_RING3_LIN into PROT_MASK Paolo Bonzini
2026-03-23 14:49 ` Jon Kohler
2026-03-25 4:29 ` Huang, Kai
2026-03-21 0:09 ` [PATCH 02/22] KVM: x86/mmu: remove SPTE_PERM_MASK Paolo Bonzini
2026-03-25 4:29 ` Huang, Kai
2026-03-21 0:09 ` [PATCH 03/22] KVM: x86/mmu: adjust MMIO generation bit allocation and allowed mask Paolo Bonzini
2026-03-24 3:48 ` Huang, Kai
2026-03-24 9:11 ` Paolo Bonzini [this message]
2026-03-21 0:09 ` [PATCH 04/22] KVM: x86/mmu: shuffle high bits of SPTEs in preparation for MBEC Paolo Bonzini
2026-03-25 4:35 ` Huang, Kai
2026-03-21 0:09 ` [PATCH 05/22] KVM: x86/mmu: remove SPTE_EPT_* Paolo Bonzini
2026-03-25 4:36 ` Huang, Kai
2026-03-21 0:09 ` [PATCH 06/22] KVM: x86/mmu: merge make_spte_{non,}executable Paolo Bonzini
2026-03-23 14:49 ` Jon Kohler
2026-03-21 0:09 ` [PATCH 07/22] KVM: x86/mmu: rename and clarify BYTE_MASK Paolo Bonzini
2026-03-21 0:09 ` [PATCH 08/22] KVM: x86/mmu: introduce ACC_READ_MASK Paolo Bonzini
2026-03-23 14:49 ` Jon Kohler
2026-03-23 14:49 ` Jon Kohler
2026-03-21 0:09 ` [PATCH 09/22] KVM: x86/mmu: separate more EPT/non-EPT permission_fault() Paolo Bonzini
2026-03-21 0:09 ` [PATCH 10/22] KVM: x86/mmu: split XS/XU bits for MBEC Paolo Bonzini
2026-03-24 10:45 ` Huang, Kai
2026-03-24 11:24 ` Paolo Bonzini
2026-03-25 4:28 ` Huang, Kai
2026-03-21 0:09 ` [PATCH 11/22] KVM: x86/mmu: move cr4_smep to base role Paolo Bonzini
2026-03-21 0:09 ` [PATCH 12/22] KVM: VMX: enable use of MBEC Paolo Bonzini
2026-03-23 14:49 ` Jon Kohler
2026-03-21 0:09 ` [PATCH 13/22] KVM: x86/mmu: add support for nested MBEC Paolo Bonzini
2026-03-23 14:49 ` Jon Kohler
2026-03-21 0:09 ` [PATCH 14/22] KVM: nVMX: advertise MBEC to nested guests Paolo Bonzini
2026-03-23 14:49 ` Jon Kohler
2026-03-21 0:09 ` [PATCH 15/22] KVM: nVMX: allow MBEC with EVMCS Paolo Bonzini
2026-03-21 0:09 ` [PATCH 16/22] KVM: x86/tdp_mmu: propagate access mask from kvm_mmu_page to PTE Paolo Bonzini
2026-03-21 0:09 ` [PATCH 17/22] KVM: x86/mmu: introduce cpu_role bit for availability of PFEC.I/D Paolo Bonzini
2026-03-21 0:09 ` [PATCH 18/22] KVM: SVM: add GMET bit definitions Paolo Bonzini
2026-03-21 11:58 ` Borislav Petkov
2026-03-21 13:51 ` Paolo Bonzini
2026-03-21 15:42 ` Borislav Petkov
2026-03-23 7:53 ` Paolo Bonzini
2026-03-23 12:17 ` Borislav Petkov
2026-03-23 12:22 ` Paolo Bonzini
2026-03-23 12:26 ` Borislav Petkov
2026-03-23 12:19 ` Borislav Petkov
2026-03-23 12:26 ` Borislav Petkov
2026-03-21 0:09 ` [PATCH 19/22] KVM: x86/mmu: add support for NPT GMET Paolo Bonzini
2026-03-21 0:09 ` [PATCH 20/22] KVM: SVM: enable GMET and set it in MMU role Paolo Bonzini
2026-03-25 9:25 ` Nikunj A. Dadhania
2026-03-25 9:29 ` Paolo Bonzini
2026-03-25 9:39 ` Nikunj A. Dadhania
2026-03-25 10:08 ` Paolo Bonzini
2026-03-21 0:09 ` [PATCH 21/22] KVM: SVM: work around errata 1218 Paolo Bonzini
2026-03-21 0:09 ` [PATCH 22/22] KVM: nSVM: enable GMET for guests Paolo Bonzini
2026-03-24 19:57 ` Jon Kohler
2026-03-25 5:22 ` Nikunj A. Dadhania
2026-03-25 12:55 ` Paolo Bonzini
2026-03-21 13:54 ` [RFC PATCH 00/22] KVM: combined patchset for MBEC/GMET support Paolo Bonzini
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