From: Eduardo Habkost <ehabkost-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Avi Kivity <avi-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Andrew Morton <akpm-3NddpPZAyC0@public.gmane.org>,
kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"Rafael J. Wysocki" <rjw-KKrjLPT3xs0@public.gmane.org>,
Haren Myneni <hbabu-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>,
Simon Horman <horms-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>,
"Eric W. Biederman"
<ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>,
Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>,
Andrey Borzenkov <arvidjaar-JGs/UdohzUI@public.gmane.org>,
mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH 08/16] x86: Emergency virtualization disable function
Date: Thu, 6 Nov 2008 15:45:38 -0200 [thread overview]
Message-ID: <20081106174538.GU5247@blackpad> (raw)
In-Reply-To: <4912C75B.8050508-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
On Thu, Nov 06, 2008 at 12:30:51PM +0200, Avi Kivity wrote:
> Eric W. Biederman wrote:
>>
>>> If you want to be extra simple and safe, remove kvm from the equation. Make the
>>> disabling code part of kdump/emergency_restart and only rely on the convention
>>> that cr3.vmxe == vmxon.
>>>
>> Convention?
>>
>
> There is a de-facto convention supported by at least vmware and kvm. If
> cr4.vmxe is 1, then we are in vmx operation. If cr4.vmxe is 0, then we
> are not in vmx operation. This allows us to determine whether we need
> to execute vmxoff without any APIs.
I am just worried about the probing needed to make sure CR4 is available
(and that the CR4.VMXE bit means what we expect it to mean), before we
try to read it and check VMXE. The same for SVM and the MSRs we need to
touch to disable SVM.
I prefer to reuse code that already exists on KVM and is working than
adding new probing code that I won't be able to test on all hardware
configurations.
--
Eduardo
next prev parent reply other threads:[~2008-11-06 17:45 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-04 14:52 [PATCH 00/14] x86: disable virt on kdump and emergency_restart Eduardo Habkost
2008-11-04 14:52 ` [PATCH 01/16] x86 kdump: Extract kdump-specific code from crash_nmi_callback() Eduardo Habkost
2008-11-04 14:52 ` [PATCH 02/16] x86 kdump: Move crashing_cpu assignment to nmi_shootdown_cpus() Eduardo Habkost
2008-11-04 14:52 ` [PATCH 03/16] x86 kdump: Create kdump_nmi_shootdown_cpus() Eduardo Habkost
2008-11-04 14:52 ` [PATCH 04/16] x86 kdump: Make kdump_nmi_callback() a function ptr on crash_nmi_callback() Eduardo Habkost
2008-11-04 14:52 ` [PATCH 05/16] x86 kdump: Make nmi_shootdown_cpus() non-static Eduardo Habkost
2008-11-04 14:52 ` [PATCH 06/16] x86: Move nmi_shootdown_cpus() to reboot.c Eduardo Habkost
2008-11-04 14:52 ` [PATCH 07/16] x86: Make nmi_shootdown_cpus() available on !SMP and !X86_LOCAL_APIC Eduardo Habkost
2008-11-04 18:15 ` Eduardo Habkost
2008-11-04 14:52 ` [PATCH 08/16] x86: Emergency virtualization disable function Eduardo Habkost
2008-11-05 17:33 ` Eric W. Biederman
[not found] ` <m1bpwu3wod.fsf-B27657KtZYmhTnVgQlOflh2eb7JE58TQ@public.gmane.org>
2008-11-05 17:52 ` Eduardo Habkost
2008-11-06 9:48 ` Avi Kivity
2008-11-06 10:22 ` Eric W. Biederman
[not found] ` <m1mygd2lxs.fsf-B27657KtZYmhTnVgQlOflh2eb7JE58TQ@public.gmane.org>
2008-11-06 10:30 ` Avi Kivity
[not found] ` <4912C75B.8050508-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-11-06 17:45 ` Eduardo Habkost [this message]
2008-11-09 11:23 ` Avi Kivity
2008-11-04 14:52 ` [PATCH 09/16] kdump: Hook emergency_virt_disable() on crash shutdown code Eduardo Habkost
[not found] ` <1225810364-8990-10-git-send-email-ehabkost-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-11-05 14:41 ` Vivek Goyal
[not found] ` <20081105144144.GC8993-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-11-05 15:07 ` Eduardo Habkost
2008-11-04 14:52 ` [PATCH 10/16] x86: disable virtualization on all CPUs if needed, on emergency_restart Eduardo Habkost
2008-11-04 14:52 ` [PATCH 11/16] kvm_x86_ops: crash_hardware_disable() operation Eduardo Habkost
2008-11-04 14:52 ` [PATCH 12/16] kvm: svm: set crash_hardware_disable to svm_hardware_disable Eduardo Habkost
2008-11-04 14:52 ` [PATCH 13/16] kvm: vmx: crash_hardware_disable function Eduardo Habkost
2008-11-04 14:52 ` [PATCH 14/16] kvmx: x86: set kvm_x86_ops earlier on kvm_arch_init() Eduardo Habkost
2008-11-04 14:52 ` [PATCH 15/16] kvm: x86: set kdump virt_disable function on initialization Eduardo Habkost
2008-11-05 17:26 ` Eric W. Biederman
[not found] ` <m1od0u3wyq.fsf-B27657KtZYmhTnVgQlOflh2eb7JE58TQ@public.gmane.org>
2008-11-05 17:50 ` Eduardo Habkost
2008-11-06 9:44 ` Avi Kivity
2008-11-04 14:52 ` [PATCH 16/16] Revert "x86: default to reboot via ACPI" Eduardo Habkost
[not found] ` <1225810364-8990-1-git-send-email-ehabkost-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-11-04 16:54 ` [PATCH 00/14] x86: disable virt on kdump and emergency_restart Avi Kivity
2008-11-05 14:44 ` Vivek Goyal
2008-11-05 15:04 ` Eduardo Habkost
2008-11-06 9:52 ` Avi Kivity
[not found] ` <49107E2C.8090803-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-11-05 16:33 ` Ingo Molnar
[not found] ` <20081105163306.GA30018-X9Un+BFzKDI@public.gmane.org>
2008-11-06 9:49 ` Avi Kivity
[not found] ` <4912BDC5.3000508-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-11-06 12:28 ` Eduardo Habkost
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