* [PATCH] KVM: MMU: Disassociate direct maps from guest levels @ 2010-03-14 8:22 Avi Kivity 2010-03-17 18:16 ` Marcelo Tosatti 0 siblings, 1 reply; 6+ messages in thread From: Avi Kivity @ 2010-03-14 8:22 UTC (permalink / raw) To: Marcelo Tosatti; +Cc: kvm Direct maps are linear translations for a section of memory, used for real mode or with large pages. As such, they are independent of the guest levels. Teach the mmu about this by making page->role.glevels = 0 for direct maps. This allows direct maps to be shared among real mode and the various paging modes. Signed-off-by: Avi Kivity <avi@redhat.com> --- arch/x86/kvm/mmu.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b137515..a984bc1 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1328,6 +1328,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, role = vcpu->arch.mmu.base_role; role.level = level; role.direct = direct; + if (role.direct) + role.glevels = 0; role.access = access; if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) { quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level)); -- 1.7.0.2 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: MMU: Disassociate direct maps from guest levels 2010-03-14 8:22 [PATCH] KVM: MMU: Disassociate direct maps from guest levels Avi Kivity @ 2010-03-17 18:16 ` Marcelo Tosatti 2010-03-23 10:51 ` Avi Kivity 0 siblings, 1 reply; 6+ messages in thread From: Marcelo Tosatti @ 2010-03-17 18:16 UTC (permalink / raw) To: Avi Kivity; +Cc: kvm On Sun, Mar 14, 2010 at 10:22:52AM +0200, Avi Kivity wrote: > Direct maps are linear translations for a section of memory, used for > real mode or with large pages. As such, they are independent of the guest > levels. > > Teach the mmu about this by making page->role.glevels = 0 for direct maps. > This allows direct maps to be shared among real mode and the various paging > modes. > > Signed-off-by: Avi Kivity <avi@redhat.com> > --- > arch/x86/kvm/mmu.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index b137515..a984bc1 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -1328,6 +1328,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, > role = vcpu->arch.mmu.base_role; > role.level = level; > role.direct = direct; > + if (role.direct) > + role.glevels = 0; > role.access = access; > if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) { > quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level)); > -- > 1.7.0.2 Isnt this what happens already, since for tdp base_role.glevels is not initialized? ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: MMU: Disassociate direct maps from guest levels 2010-03-17 18:16 ` Marcelo Tosatti @ 2010-03-23 10:51 ` Avi Kivity 2010-03-23 11:01 ` Joerg Roedel 2010-03-23 11:02 ` Avi Kivity 0 siblings, 2 replies; 6+ messages in thread From: Avi Kivity @ 2010-03-23 10:51 UTC (permalink / raw) To: Marcelo Tosatti, Joerg Roedel; +Cc: kvm On 03/17/2010 08:16 PM, Marcelo Tosatti wrote: > On Sun, Mar 14, 2010 at 10:22:52AM +0200, Avi Kivity wrote: > >> Direct maps are linear translations for a section of memory, used for >> real mode or with large pages. As such, they are independent of the guest >> levels. >> >> Teach the mmu about this by making page->role.glevels = 0 for direct maps. >> This allows direct maps to be shared among real mode and the various paging >> modes. >> >> @@ -1328,6 +1328,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, >> role = vcpu->arch.mmu.base_role; >> role.level = level; >> role.direct = direct; >> + if (role.direct) >> + role.glevels = 0; >> role.access = access; >> if (vcpu->arch.mmu.root_level<= PT32_ROOT_LEVEL) { >> quadrant = gaddr>> (PAGE_SHIFT + (PT64_PT_BITS * level)); >> -- >> 1.7.0.2 >> > Isnt this what happens already, since for tdp base_role.glevels is not > initialized? > Correct. I was thinking about the nested npt case, which will use role.glevels. Joerg, please incorporate this into your nnpt patchset. -- error compiling committee.c: too many arguments to function ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: MMU: Disassociate direct maps from guest levels 2010-03-23 10:51 ` Avi Kivity @ 2010-03-23 11:01 ` Joerg Roedel 2010-03-23 11:02 ` Avi Kivity 1 sibling, 0 replies; 6+ messages in thread From: Joerg Roedel @ 2010-03-23 11:01 UTC (permalink / raw) To: Avi Kivity; +Cc: Marcelo Tosatti, Joerg Roedel, kvm On Tue, Mar 23, 2010 at 12:51:15PM +0200, Avi Kivity wrote: > On 03/17/2010 08:16 PM, Marcelo Tosatti wrote: >> On Sun, Mar 14, 2010 at 10:22:52AM +0200, Avi Kivity wrote: >> >>> Direct maps are linear translations for a section of memory, used for >>> real mode or with large pages. As such, they are independent of the guest >>> levels. >>> >>> Teach the mmu about this by making page->role.glevels = 0 for direct maps. >>> This allows direct maps to be shared among real mode and the various paging >>> modes. >>> >>> @@ -1328,6 +1328,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, >>> role = vcpu->arch.mmu.base_role; >>> role.level = level; >>> role.direct = direct; >>> + if (role.direct) >>> + role.glevels = 0; >>> role.access = access; >>> if (vcpu->arch.mmu.root_level<= PT32_ROOT_LEVEL) { >>> quadrant = gaddr>> (PAGE_SHIFT + (PT64_PT_BITS * level)); >>> -- >>> 1.7.0.2 >>> >> Isnt this what happens already, since for tdp base_role.glevels is not >> initialized? >> > > Correct. I was thinking about the nested npt case, which will use > role.glevels. Joerg, please incorporate this into your nnpt patchset. Yes will do. I am currently out-of-office until April 6th. Expect a re-send of the patch-set some time after that :-) Joerg ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: MMU: Disassociate direct maps from guest levels 2010-03-23 10:51 ` Avi Kivity 2010-03-23 11:01 ` Joerg Roedel @ 2010-03-23 11:02 ` Avi Kivity 2010-03-23 13:59 ` Marcelo Tosatti 1 sibling, 1 reply; 6+ messages in thread From: Avi Kivity @ 2010-03-23 11:02 UTC (permalink / raw) To: Marcelo Tosatti, Joerg Roedel; +Cc: kvm On 03/23/2010 12:51 PM, Avi Kivity wrote: > On 03/17/2010 08:16 PM, Marcelo Tosatti wrote: >> On Sun, Mar 14, 2010 at 10:22:52AM +0200, Avi Kivity wrote: >>> Direct maps are linear translations for a section of memory, used for >>> real mode or with large pages. As such, they are independent of the >>> guest >>> levels. >>> >>> Teach the mmu about this by making page->role.glevels = 0 for direct >>> maps. >>> This allows direct maps to be shared among real mode and the various >>> paging >>> modes. >>> >>> @@ -1328,6 +1328,8 @@ static struct kvm_mmu_page >>> *kvm_mmu_get_page(struct kvm_vcpu *vcpu, >>> role = vcpu->arch.mmu.base_role; >>> role.level = level; >>> role.direct = direct; >>> + if (role.direct) >>> + role.glevels = 0; >>> role.access = access; >>> if (vcpu->arch.mmu.root_level<= PT32_ROOT_LEVEL) { >>> quadrant = gaddr>> (PAGE_SHIFT + (PT64_PT_BITS * level)); >>> -- >>> 1.7.0.2 >> Isnt this what happens already, since for tdp base_role.glevels is not >> initialized? > > Correct. I was thinking about the nested npt case, which will use > role.glevels. Joerg, please incorporate this into your nnpt patchset. > Actually, incorrect. This patch is also applicable to non-tdp (which is the same case as nnpt). It will allow reusing real-mode direct maps and large page mappings from the various modes. It won't make any performance difference, it's more a documentation aid that direct maps aren't dependent on the guest at all, except for permissions. -- error compiling committee.c: too many arguments to function ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: MMU: Disassociate direct maps from guest levels 2010-03-23 11:02 ` Avi Kivity @ 2010-03-23 13:59 ` Marcelo Tosatti 0 siblings, 0 replies; 6+ messages in thread From: Marcelo Tosatti @ 2010-03-23 13:59 UTC (permalink / raw) To: Avi Kivity; +Cc: Joerg Roedel, kvm On Tue, Mar 23, 2010 at 01:02:35PM +0200, Avi Kivity wrote: > On 03/23/2010 12:51 PM, Avi Kivity wrote: > >On 03/17/2010 08:16 PM, Marcelo Tosatti wrote: > >>On Sun, Mar 14, 2010 at 10:22:52AM +0200, Avi Kivity wrote: > >>>Direct maps are linear translations for a section of memory, used for > >>>real mode or with large pages. As such, they are independent > >>>of the guest > >>>levels. > >>> > >>>Teach the mmu about this by making page->role.glevels = 0 for > >>>direct maps. > >>>This allows direct maps to be shared among real mode and the > >>>various paging > >>>modes. > >>> > >>>@@ -1328,6 +1328,8 @@ static struct kvm_mmu_page > >>>*kvm_mmu_get_page(struct kvm_vcpu *vcpu, > >>> role = vcpu->arch.mmu.base_role; > >>> role.level = level; > >>> role.direct = direct; > >>>+ if (role.direct) > >>>+ role.glevels = 0; > >>> role.access = access; > >>> if (vcpu->arch.mmu.root_level<= PT32_ROOT_LEVEL) { > >>> quadrant = gaddr>> (PAGE_SHIFT + (PT64_PT_BITS * level)); > >>>-- > >>>1.7.0.2 > >>Isnt this what happens already, since for tdp base_role.glevels is not > >>initialized? > > > >Correct. I was thinking about the nested npt case, which will use > >role.glevels. Joerg, please incorporate this into your nnpt > >patchset. > > > > Actually, incorrect. This patch is also applicable to non-tdp > (which is the same case as nnpt). It will allow reusing real-mode > direct maps and large page mappings from the various modes. It > won't make any performance difference, it's more a documentation aid > that direct maps aren't dependent on the guest at all, except for > permissions. Sure, makes sense. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-03-23 14:00 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2010-03-14 8:22 [PATCH] KVM: MMU: Disassociate direct maps from guest levels Avi Kivity 2010-03-17 18:16 ` Marcelo Tosatti 2010-03-23 10:51 ` Avi Kivity 2010-03-23 11:01 ` Joerg Roedel 2010-03-23 11:02 ` Avi Kivity 2010-03-23 13:59 ` Marcelo Tosatti
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