From: "Shah, Amit" <Amit.Shah@amd.com>
To: "seanjc@google.com" <seanjc@google.com>
Cc: "x86@kernel.org" <x86@kernel.org>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"bp@alien8.de" <bp@alien8.de>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"jon@nutanix.com" <jon@nutanix.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 06/18] KVM: VMX: Wire up Intel MBEC enable/disable logic
Date: Wed, 9 Jul 2025 13:40:16 +0000 [thread overview]
Message-ID: <d530621e89dae01dc27bbdc8a97a1935b0827699.camel@amd.com> (raw)
In-Reply-To: <aFF38Pq71JdLBlqO@google.com>
On Tue, 2025-06-17 at 07:13 -0700, Sean Christopherson wrote:
> [snipped nested page walk overview]
Thanks a lot for this!
>
> Side topic, someone should check with the AMD architects as to
> whether or not
> GMET depends on EFER.NXE=1. The APM says that all NPT mappings are
> executable
> if EFER.NXE=0 in the host (where the "host" is L1 when dealing with
> nested NPT).
> To me, that implies GMET is effectively ignored if EFER.NXE=0.
>
> Similarly, if the EFER.NXE bit is cleared for the host, all nested
> page table
> mappings are executable at the underlying nested level.
The "effective NX" computation includes EFER.NXE. If that's 0, GMET is
still active and depends on the U/S bit if enabled, as mentioned in the
APM.
Cheers,
Amit
next prev parent reply other threads:[~2025-07-09 13:40 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-13 20:36 [RFC PATCH 00/18] KVM: VMX: Introduce Intel Mode-Based Execute Control (MBEC) Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 01/18] KVM: VMX: Remove EPT_VIOLATIONS_ACC_*_BIT defines Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 02/18] KVM: nVMX: Decouple EPT RWX bits from EPT Violation protection bits Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 03/18] KVM: x86: Add module parameter for Intel MBEC Jon Kohler
2025-05-12 18:08 ` Sean Christopherson
2025-05-13 2:18 ` Jon Kohler
2025-05-13 7:57 ` Shah, Amit
2025-03-13 20:36 ` [RFC PATCH 04/18] KVM: VMX: add cpu_has_vmx_mbec helper Jon Kohler
2025-05-12 18:14 ` Sean Christopherson
2025-05-13 2:17 ` Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 05/18] KVM: x86: Add pt_guest_exec_control to kvm_vcpu_arch Jon Kohler
2025-04-22 6:27 ` Chao Gao
2025-05-12 18:15 ` Sean Christopherson
2025-03-13 20:36 ` [RFC PATCH 06/18] KVM: VMX: Wire up Intel MBEC enable/disable logic Jon Kohler
2025-04-22 7:06 ` Chao Gao
2025-05-12 18:23 ` Sean Christopherson
2025-05-13 2:16 ` Jon Kohler
2025-05-13 13:28 ` Sean Christopherson
2025-05-14 11:14 ` Shah, Amit
2025-05-14 12:55 ` Sean Christopherson
2025-06-16 9:27 ` Shah, Amit
2025-06-17 14:13 ` Sean Christopherson
2025-07-09 13:40 ` Shah, Amit [this message]
2025-03-13 20:36 ` [RFC PATCH 07/18] KVM: VMX: Define VMX_EPT_USER_EXECUTABLE_MASK Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 08/18] KVM: x86/mmu: Remove SPTE_PERM_MASK Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 09/18] KVM: x86/mmu: Extend access bitfield in kvm_mmu_page_role Jon Kohler
2025-05-12 18:32 ` Sean Christopherson
2025-05-13 2:14 ` Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 10/18] KVM: VMX: Extend EPT Violation protection bits Jon Kohler
2025-05-12 18:37 ` Sean Christopherson
2025-03-13 20:36 ` [RFC PATCH 11/18] KVM: VMX: Enhance EPT violation handler for PROT_USER_EXEC Jon Kohler
2025-05-12 18:54 ` Sean Christopherson
2025-03-13 20:36 ` [RFC PATCH 12/18] KVM: x86/mmu: Introduce shadow_ux_mask Jon Kohler
2025-04-23 3:06 ` Chao Gao
2025-05-12 19:13 ` Sean Christopherson
2025-03-13 20:36 ` [RFC PATCH 13/18] KVM: x86/mmu: Adjust SPTE_MMIO_ALLOWED_MASK to understand MBEC Jon Kohler
2025-04-23 5:37 ` Chao Gao
2025-05-12 19:37 ` Sean Christopherson
2025-05-13 2:11 ` Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 14/18] KVM: x86/mmu: Extend is_executable_pte " Jon Kohler
2025-04-23 6:16 ` Chao Gao
2025-05-12 21:16 ` Sean Christopherson
2025-05-13 2:09 ` Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 15/18] KVM: x86/mmu: Extend make_spte " Jon Kohler
2025-05-12 21:29 ` Sean Christopherson
2025-05-13 2:04 ` Jon Kohler
2025-05-13 17:54 ` Sean Christopherson
2025-03-13 20:36 ` [RFC PATCH 16/18] KVM: nVMX: Setup Intel MBEC in nested secondary controls Jon Kohler
2025-05-12 21:32 ` Sean Christopherson
2025-03-13 20:36 ` [RFC PATCH 17/18] KVM: VMX: Allow MBEC with EVMCS Jon Kohler
2025-05-12 21:35 ` Sean Christopherson
2025-05-13 2:01 ` Jon Kohler
2025-03-13 20:36 ` [RFC PATCH 18/18] KVM: x86: Enable module parameter for MBEC Jon Kohler
2025-04-15 9:29 ` [RFC PATCH 00/18] KVM: VMX: Introduce Intel Mode-Based Execute Control (MBEC) Mickaël Salaün
2025-04-15 14:43 ` Sean Christopherson
2025-05-12 15:26 ` Jon Kohler
2025-04-15 14:43 ` Jon Kohler
2025-04-16 15:44 ` Mickaël Salaün
2025-04-23 13:54 ` Adrian-Ken Rueegsegger
2025-05-12 15:26 ` Jon Kohler
2025-05-12 21:46 ` Sean Christopherson
2025-05-13 1:59 ` Jon Kohler
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