* [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
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.