From: Avi Kivity <avi@redhat.com>
To: "Nadav Har'El" <nyh@il.ibm.com>
Cc: kvm@vger.kernel.org, gleb@redhat.com
Subject: Re: [PATCH 04/27] nVMX: Allow setting the VMXE bit in CR4
Date: Sun, 17 Oct 2010 14:31:16 +0200 [thread overview]
Message-ID: <4CBAEC94.9050102@redhat.com> (raw)
In-Reply-To: <201010171005.o9HA5bWm029315@rice.haifa.ibm.com>
On 10/17/2010 12:05 PM, Nadav Har'El wrote:
> This patch allows the guest to enable the VMXE bit in CR4, which is a
> prerequisite to running VMXON.
>
> Whether to allow setting the VMXE bit now depends on the architecture (svm
> or vmx), so its checking has moved to kvm_x86_ops->set_cr4(). This function
> now returns an int: If kvm_x86_ops->set_cr4() returns 1, __kvm_set_cr4()
> will also return 1, and this will cause kvm_set_cr4() will throw a #GP.
>
> Turning on the VMXE bit is allowed only when the "nested" module option is on,
> and turning it off is forbidden after a vmxon.
>
>
>
> -static void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
> +static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
> {
> unsigned long hw_cr4 = cr4 | (to_vmx(vcpu)->rmode.vm86_active ?
> KVM_RMODE_VM_CR4_ALWAYS_ON : KVM_PMODE_VM_CR4_ALWAYS_ON);
>
> + if (cr4& X86_CR4_VMXE){
> + if (!nested)
> + return 1;
Need to check cpuid.vmx as well, otherwise we can't turn off vmx for
specific guests (only for the entire machine).
> + } else {
> + if (nested&& to_vmx(vcpu)->nested.vmxon)
> + return 1;
> + }
> +
Unrelated, if nested.vmxon, shouldn't we forbid clearing certain bits of
cr0?
It occurs to me that these bits are not fixed, instead specified by an
MSR. So we can simply have the MSR allow them (if we're sure that it
would work; don't see why not).
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2010-10-17 12:31 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-17 10:03 [PATCH 0/27] nVMX: Nested VMX, v6 Nadav Har'El
2010-10-17 10:04 ` [PATCH 01/27] nVMX: Add "nested" module option to vmx.c Nadav Har'El
2010-10-17 10:04 ` [PATCH 02/27] nVMX: Add VMX and SVM to list of supported cpuid features Nadav Har'El
2010-10-17 10:05 ` [PATCH 03/27] nVMX: Implement VMXON and VMXOFF Nadav Har'El
2010-10-17 12:24 ` Avi Kivity
2010-10-17 12:47 ` Nadav Har'El
2010-10-17 13:07 ` Avi Kivity
2010-10-17 10:05 ` [PATCH 04/27] nVMX: Allow setting the VMXE bit in CR4 Nadav Har'El
2010-10-17 12:31 ` Avi Kivity [this message]
2010-10-17 10:06 ` [PATCH 05/27] nVMX: Introduce vmcs12: a VMCS structure for L1 Nadav Har'El
2010-10-17 12:34 ` Avi Kivity
2010-10-17 13:18 ` Nadav Har'El
2010-10-17 13:29 ` Avi Kivity
2010-10-17 10:06 ` [PATCH 06/27] nVMX: Implement reading and writing of VMX MSRs Nadav Har'El
2010-10-17 12:52 ` Avi Kivity
2010-10-17 10:07 ` [PATCH 07/27] nVMX: Decoding memory operands of VMX instructions Nadav Har'El
2010-10-17 10:07 ` [PATCH 08/27] nVMX: Hold a vmcs02 for each vmcs12 Nadav Har'El
2010-10-17 13:00 ` Avi Kivity
2010-10-17 10:08 ` [PATCH 09/27] nVMX: Success/failure of VMX instructions Nadav Har'El
2010-10-17 10:08 ` [PATCH 10/27] nVMX: Implement VMCLEAR Nadav Har'El
2010-10-17 13:05 ` Avi Kivity
2010-10-17 13:25 ` Nadav Har'El
2010-10-17 13:27 ` Avi Kivity
2010-10-17 13:37 ` Nadav Har'El
2010-10-17 14:12 ` Avi Kivity
2010-10-17 14:14 ` Gleb Natapov
2010-10-17 10:09 ` [PATCH 11/27] nVMX: Implement VMPTRLD Nadav Har'El
2010-10-17 10:09 ` [PATCH 12/27] nVMX: Implement VMPTRST Nadav Har'El
2010-10-17 10:10 ` [PATCH 13/27] nVMX: Add VMCS fields to the vmcs12 Nadav Har'El
2010-10-17 13:15 ` Avi Kivity
2010-10-17 10:10 ` [PATCH 14/27] nVMX: Implement VMREAD and VMWRITE Nadav Har'El
2010-10-17 13:25 ` Avi Kivity
2010-10-17 10:11 ` [PATCH 15/27] nVMX: Prepare vmcs02 from vmcs01 and vmcs12 Nadav Har'El
2010-10-17 14:08 ` Avi Kivity
2011-02-08 12:13 ` Nadav Har'El
2011-02-08 12:27 ` Avi Kivity
2011-02-08 12:36 ` Nadav Har'El
2011-02-08 12:39 ` Avi Kivity
2011-02-08 12:27 ` Avi Kivity
2010-10-17 10:11 ` [PATCH 16/27] nVMX: Move register-syncing to a function Nadav Har'El
2010-10-17 10:12 ` [PATCH 17/27] nVMX: Implement VMLAUNCH and VMRESUME Nadav Har'El
2010-10-17 15:06 ` Avi Kivity
2010-10-17 10:12 ` [PATCH 18/27] nVMX: No need for handle_vmx_insn function any more Nadav Har'El
2010-10-17 10:13 ` [PATCH 19/27] nVMX: Exiting from L2 to L1 Nadav Har'El
2010-10-17 15:58 ` Avi Kivity
2010-10-17 10:13 ` [PATCH 20/27] nVMX: Deciding if L0 or L1 should handle an L2 exit Nadav Har'El
2010-10-20 12:13 ` Avi Kivity
2010-10-20 14:57 ` Avi Kivity
2010-10-17 10:14 ` [PATCH 21/27] nVMX: Correct handling of interrupt injection Nadav Har'El
2010-10-17 10:14 ` [PATCH 22/27] nVMX: Correct handling of exception injection Nadav Har'El
2010-10-17 10:15 ` [PATCH 23/27] nVMX: Correct handling of idt vectoring info Nadav Har'El
2010-10-17 10:15 ` [PATCH 24/27] nVMX: Handling of CR0.TS and #NM for Lazy FPU loading Nadav Har'El
2010-10-17 10:16 ` [PATCH 25/27] nVMX: Additional TSC-offset handling Nadav Har'El
2010-10-19 19:13 ` Zachary Amsden
2010-10-17 10:16 ` [PATCH 26/27] nVMX: Miscellenous small corrections Nadav Har'El
2010-10-17 10:17 ` [PATCH 27/27] nVMX: Documentation Nadav Har'El
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