From: "Huang, Kai" <kai.huang@intel.com>
To: "tglx@linutronix.de" <tglx@linutronix.de>,
"x86@kernel.org" <x86@kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>, "Christopherson,,
Sean" <seanjc@google.com>, "bp@alien8.de" <bp@alien8.de>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Gao, Chao" <chao.gao@intel.com>,
"andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>
Subject: Re: [PATCH v4 07/19] x86/reboot: Disable virtualization during reboot iff callback is registered
Date: Mon, 24 Jul 2023 23:57:46 +0000 [thread overview]
Message-ID: <7fcc0a4b3b653bfc9c031a3ca060e4cd14119228.camel@intel.com> (raw)
In-Reply-To: <20230721201859.2307736-8-seanjc@google.com>
On Fri, 2023-07-21 at 13:18 -0700, Sean Christopherson wrote:
> Attempt to disable virtualization during an emergency reboot if and only
> if there is a registered virt callback, i.e. iff a hypervisor (KVM) is
> active. If there's no active hypervisor, then the CPU can't be operating
> with VMX or SVM enabled (barring an egregious bug).
>
> Checking for a valid callback instead of simply for SVM or VMX support
> can also eliminates spurious NMIs by avoiding the unecessary call to
> nmi_shootdown_cpus_on_restart().
>
> Note, IRQs are disabled, which prevents KVM from coming along and
> enabling virtualization after the fact.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
>
Reviewed-by: Kai Huang <kai.huang@intel.com>
next prev parent reply other threads:[~2023-07-24 23:57 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-21 20:18 [PATCH v4 00/19] x86/reboot: KVM: Clean up "emergency" virt code Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 01/19] x86/reboot: VMCLEAR active VMCSes before emergency reboot Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 02/19] x86/reboot: Harden virtualization hooks for " Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 03/19] x86/reboot: KVM: Handle VMXOFF in KVM's reboot callback Sean Christopherson
2023-07-24 23:57 ` Huang, Kai
2023-07-21 20:18 ` [PATCH v4 04/19] x86/reboot: KVM: Disable SVM during reboot via virt/KVM " Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 05/19] x86/reboot: Assert that IRQs are disabled when turning off virtualization Sean Christopherson
2023-07-24 21:19 ` Peter Zijlstra
2023-07-24 21:41 ` Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 06/19] x86/reboot: Hoist "disable virt" helpers above "emergency reboot" path Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 07/19] x86/reboot: Disable virtualization during reboot iff callback is registered Sean Christopherson
2023-07-24 23:57 ` Huang, Kai [this message]
2023-07-21 20:18 ` [PATCH v4 08/19] x86/reboot: Expose VMCS crash hooks if and only if KVM_{INTEL,AMD} is enabled Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 09/19] x86/virt: KVM: Open code cpu_has_vmx() in KVM VMX Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 10/19] x86/virt: KVM: Move VMXOFF helpers into " Sean Christopherson
2023-07-28 9:08 ` Xu Yilun
2023-07-28 9:43 ` Huang, Kai
2023-07-21 20:18 ` [PATCH v4 11/19] KVM: SVM: Make KVM_AMD depend on CPU_SUP_AMD or CPU_SUP_HYGON Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 12/19] x86/virt: Drop unnecessary check on extended CPUID level in cpu_has_svm() Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 13/19] x86/virt: KVM: Open code cpu_has_svm() into kvm_is_svm_supported() Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 14/19] KVM: SVM: Check that the current CPU supports SVM in kvm_is_svm_supported() Sean Christopherson
2023-07-24 21:21 ` Peter Zijlstra
2023-07-24 21:40 ` Sean Christopherson
2023-07-25 9:16 ` Peter Zijlstra
2023-07-27 16:39 ` Sean Christopherson
2023-07-24 22:29 ` Dmitry Torokhov
2023-07-24 23:53 ` Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 15/19] KVM: VMX: Ensure CPU is stable when probing basic VMX support Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 16/19] x86/virt: KVM: Move "disable SVM" helper into KVM SVM Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 17/19] KVM: x86: Force kvm_rebooting=true during emergency reboot/crash Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 18/19] KVM: SVM: Use "standard" stgi() helper when disabling SVM Sean Christopherson
2023-07-21 20:18 ` [PATCH v4 19/19] KVM: VMX: Skip VMCLEAR logic during emergency reboots if CR4.VMXE=0 Sean Christopherson
2023-07-25 3:51 ` Huang, Kai
2023-07-25 18:15 ` Sean Christopherson
2023-07-25 22:20 ` Huang, Kai
2023-08-04 0:40 ` [PATCH v4 00/19] x86/reboot: KVM: Clean up "emergency" virt code Sean Christopherson
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