Userspace may know better, for example when you want to allow live migration between multiple hosts and want to calculate lowest common denominator between them.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Alexander Graf Sent: Tuesday, September 02, 2008 20:54 PM To: Alexander Graf Cc: Avi Kivity; kvm@vger.kernel.org; [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: Re: [PATCH 2/2] Allow the SVM CPUID bit in a VM On Sep 2, 2008, at 7:42 PM, Alexander Graf wrote: > > On Sep 1, 2008, at 4:00 PM, Avi Kivity wrote: > >> Alexander Graf wrote: >>> Usually the qemu-kvm-bridge removes the SVM capability flag. Since >>> KVM now >>> supports nested SVM, this is no longer necessary. >>> >>> Signed-off-by: Alexander Graf <[EMAIL PROTECTED]> >>> --- >>> qemu/qemu-kvm-x86.c | 3 --- >>> 1 files changed, 0 insertions(+), 3 deletions(-) >>> >>> diff --git a/qemu/qemu-kvm-x86.c b/qemu/qemu-kvm-x86.c >>> index 5daedd1..cfc533f 100644 >>> --- a/qemu/qemu-kvm-x86.c >>> +++ b/qemu/qemu-kvm-x86.c >>> @@ -489,9 +489,6 @@ static void do_cpuid_ent(struct >>> kvm_cpuid_entry *e, uint32_t function, >>> // nx >>> if ((h_edx & 0x00100000) == 0) >>> e->edx &= ~0x00100000u; >>> - // svm >>> - if (e->ecx & 4) >>> - e->ecx &= ~4u; >>> } >>> >> >> Needs to be predicated on a KVM_CAP_ test, so we don't enable this >> on older kvms. > > Is this a real problem? We don't allow setting SVME on older kernels > anyways. On a sidenote I'm really not fond of the userspace CPUID capability restrictions in the first place. Shouldn't this all be determined in the kernel module? It doesn't make since IMHO to restrict NX usage from userspace. The kernel module knows best what it's capable of. Alex > > > Alex > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
