* [PATCH] KVM: VMX: invalidate vpid for invlpg instruction
@ 2012-08-31 16:10 Davidlohr Bueso
2012-08-31 17:37 ` Marcelo Tosatti
0 siblings, 1 reply; 6+ messages in thread
From: Davidlohr Bueso @ 2012-08-31 16:10 UTC (permalink / raw)
To: Avi Kivity, Marcelo Tosatti; +Cc: KVM, lkml
For processors that support VPIDs we should invalidate the page table entry
specified by the lineal address. For this purpose add support for individual
address invalidations.
Signed-off-by: Davidlohr Bueso <dave@gnu.org>
---
arch/x86/include/asm/vmx.h | 6 ++++--
arch/x86/kvm/vmx.c | 15 +++++++++++++++
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 74fcb96..20abb18 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -393,6 +393,7 @@ enum vmcs_field {
#define IDENTITY_PAGETABLE_PRIVATE_MEMSLOT (KVM_MEMORY_SLOTS + 2)
#define VMX_NR_VPIDS (1 << 16)
+#define VMX_VPID_EXTENT_INDIVIDUAL_ADDR 0
#define VMX_VPID_EXTENT_SINGLE_CONTEXT 1
#define VMX_VPID_EXTENT_ALL_CONTEXT 2
@@ -406,12 +407,13 @@ enum vmcs_field {
#define VMX_EPTP_WB_BIT (1ull << 14)
#define VMX_EPT_2MB_PAGE_BIT (1ull << 16)
#define VMX_EPT_1GB_PAGE_BIT (1ull << 17)
-#define VMX_EPT_AD_BIT (1ull << 21)
+#define VMX_EPT_AD_BIT (1ull << 21)
#define VMX_EPT_EXTENT_INDIVIDUAL_BIT (1ull << 24)
#define VMX_EPT_EXTENT_CONTEXT_BIT (1ull << 25)
#define VMX_EPT_EXTENT_GLOBAL_BIT (1ull << 26)
-#define VMX_VPID_EXTENT_SINGLE_CONTEXT_BIT (1ull << 9) /* (41 - 32) */
+#define VMX_VPID_EXTENT_INDIVIDUAL_ADDR_BIT (1ull << 8) /* (40 - 32) */
+#define VMX_VPID_EXTENT_SINGLE_CONTEXT_BIT (1ull << 9) /* (41 - 32) */
#define VMX_VPID_EXTENT_GLOBAL_CONTEXT_BIT (1ull << 10) /* (42 - 32) */
#define VMX_EPT_DEFAULT_GAW 3
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c00f03d..d87b22c 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -816,6 +816,11 @@ static inline bool cpu_has_vmx_invept_global(void)
return vmx_capability.ept & VMX_EPT_EXTENT_GLOBAL_BIT;
}
+static inline bool cpu_has_vmx_invvpid_individual_addr(void)
+{
+ return vmx_capability.vpid & VMX_VPID_EXTENT_INDIVIDUAL_ADDR_BIT;
+}
+
static inline bool cpu_has_vmx_invvpid_single(void)
{
return vmx_capability.vpid & VMX_VPID_EXTENT_SINGLE_CONTEXT_BIT;
@@ -1011,6 +1016,15 @@ static void loaded_vmcs_clear(struct loaded_vmcs *loaded_vmcs)
loaded_vmcs->cpu, __loaded_vmcs_clear, loaded_vmcs, 1);
}
+static inline void vpid_sync_vcpu_individual_addr(struct vcpu_vmx *vmx, gpa_t gpa)
+{
+ if (vmx->vpid == 0)
+ return;
+
+ if (cpu_has_vmx_invvpid_individual_addr())
+ __invvpid(VMX_VPID_EXTENT_INDIVIDUAL_ADDR, vmx->vpid, gpa);
+}
+
static inline void vpid_sync_vcpu_single(struct vcpu_vmx *vmx)
{
if (vmx->vpid == 0)
@@ -4719,6 +4733,7 @@ static int handle_invlpg(struct kvm_vcpu *vcpu)
unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
kvm_mmu_invlpg(vcpu, exit_qualification);
+ vpid_sync_vcpu_individual_addr(to_vmx(vcpu), exit_qualification);
skip_emulated_instruction(vcpu);
return 1;
}
--
1.7.4.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] KVM: VMX: invalidate vpid for invlpg instruction
2012-08-31 16:10 [PATCH] KVM: VMX: invalidate vpid for invlpg instruction Davidlohr Bueso
@ 2012-08-31 17:37 ` Marcelo Tosatti
2012-09-02 23:27 ` Davidlohr Bueso
0 siblings, 1 reply; 6+ messages in thread
From: Marcelo Tosatti @ 2012-08-31 17:37 UTC (permalink / raw)
To: Davidlohr Bueso; +Cc: Avi Kivity, KVM, lkml
On Fri, Aug 31, 2012 at 06:10:48PM +0200, Davidlohr Bueso wrote:
> For processors that support VPIDs we should invalidate the page table entry
> specified by the lineal address. For this purpose add support for individual
> address invalidations.
Not necessary - a single context invalidation is performed through
KVM_REQ_TLB_FLUSH.
Single-context. If the INVVPID type is 1, the logical processor
invalidates all
linear mappings and combined mappings associated with the VPID specified
in the INVVPID descriptor.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: VMX: invalidate vpid for invlpg instruction
2012-08-31 17:37 ` Marcelo Tosatti
@ 2012-09-02 23:27 ` Davidlohr Bueso
2012-09-03 9:11 ` Avi Kivity
0 siblings, 1 reply; 6+ messages in thread
From: Davidlohr Bueso @ 2012-09-02 23:27 UTC (permalink / raw)
To: Marcelo Tosatti; +Cc: Avi Kivity, KVM, lkml
On Fri, 2012-08-31 at 14:37 -0300, Marcelo Tosatti wrote:
> On Fri, Aug 31, 2012 at 06:10:48PM +0200, Davidlohr Bueso wrote:
> > For processors that support VPIDs we should invalidate the page table entry
> > specified by the lineal address. For this purpose add support for individual
> > address invalidations.
>
> Not necessary - a single context invalidation is performed through
> KVM_REQ_TLB_FLUSH.
Since vpid_sync_context() supports both single and all-context vpid
invalidations, wouldn't it make sense to also add individual address
ones as well, supporting further granularity?
>
> Single-context. If the INVVPID type is 1, the logical processor
> invalidates all
> linear mappings and combined mappings associated with the VPID specified
> in the INVVPID descriptor.
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: VMX: invalidate vpid for invlpg instruction
2012-09-02 23:27 ` Davidlohr Bueso
@ 2012-09-03 9:11 ` Avi Kivity
2012-09-05 21:54 ` Davidlohr Bueso
0 siblings, 1 reply; 6+ messages in thread
From: Avi Kivity @ 2012-09-03 9:11 UTC (permalink / raw)
To: dave; +Cc: Marcelo Tosatti, KVM, lkml
On 09/03/2012 02:27 AM, Davidlohr Bueso wrote:
> On Fri, 2012-08-31 at 14:37 -0300, Marcelo Tosatti wrote:
>> On Fri, Aug 31, 2012 at 06:10:48PM +0200, Davidlohr Bueso wrote:
>> > For processors that support VPIDs we should invalidate the page table entry
>> > specified by the lineal address. For this purpose add support for individual
>> > address invalidations.
>>
>> Not necessary - a single context invalidation is performed through
>> KVM_REQ_TLB_FLUSH.
>
> Since vpid_sync_context() supports both single and all-context vpid
> invalidations, wouldn't it make sense to also add individual address
> ones as well, supporting further granularity?
It might. Do you have benchmarks supporting this?
--
error compiling committee.c: too many arguments to function
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: VMX: invalidate vpid for invlpg instruction
2012-09-03 9:11 ` Avi Kivity
@ 2012-09-05 21:54 ` Davidlohr Bueso
2012-09-06 8:05 ` Avi Kivity
0 siblings, 1 reply; 6+ messages in thread
From: Davidlohr Bueso @ 2012-09-05 21:54 UTC (permalink / raw)
To: Avi Kivity; +Cc: Marcelo Tosatti, KVM, lkml
On Mon, 2012-09-03 at 12:11 +0300, Avi Kivity wrote:
> On 09/03/2012 02:27 AM, Davidlohr Bueso wrote:
> > On Fri, 2012-08-31 at 14:37 -0300, Marcelo Tosatti wrote:
> >> On Fri, Aug 31, 2012 at 06:10:48PM +0200, Davidlohr Bueso wrote:
> >> > For processors that support VPIDs we should invalidate the page table entry
> >> > specified by the lineal address. For this purpose add support for individual
> >> > address invalidations.
> >>
> >> Not necessary - a single context invalidation is performed through
> >> KVM_REQ_TLB_FLUSH.
> >
> > Since vpid_sync_context() supports both single and all-context vpid
> > invalidations, wouldn't it make sense to also add individual address
> > ones as well, supporting further granularity?
>
> It might. Do you have benchmarks supporting this?
>
I ran two benchmarks: Java Dacapo[1] Sunflow (renders a set of images
using ray tracing) and a vanilla 3.2 kernel build (with 1 job and -j8).
The host configuration is an Intel i7-2635QM (4 cores + HT) with 4Gb RAM
running Linus's latest and only running standard system daemons. For KVM
I disabled EPT.
The guest configuration is a 64bit 4 core 4Gb RAM, running Linux 3.2
(debian) and only running the benchmark.
All results represent the mean of 5 runs, with time(1).
Dacapo without individual addr invvpid:
real 1m25.406s
user 4m59.315s
sys 1m25.406s
Dacapo with individual addr invvpid:
real 1m4.421s
user 3m47.150s
sys 0m1.592s
--
vanilla kernel build without individual addr invvpid:
real 16m42.571s
user 13m28.975s
sys 2m54.487s
vanilla kernel build with individual addr invvpid:
real 15m45.789s
user 12m25.691s
sys 2m44.806s
--
vanilla kernel build (-j8) without individual addr invvpid:
real 10m32.276s
user 33m47.687s
sys 5m37.725s
vanilla kernel build (-j8) with individual addr invvpid:
real 8m29.789s
user 28m12.850s
sys 4m34.353s
In all cases using individual address invalidation outperforms single
context ones regarding wall time. Comments?
[1] http://dacapobench.org/
Thanks,
Davidlohr
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] KVM: VMX: invalidate vpid for invlpg instruction
2012-09-05 21:54 ` Davidlohr Bueso
@ 2012-09-06 8:05 ` Avi Kivity
0 siblings, 0 replies; 6+ messages in thread
From: Avi Kivity @ 2012-09-06 8:05 UTC (permalink / raw)
To: dave; +Cc: Marcelo Tosatti, KVM, lkml
On 09/06/2012 12:54 AM, Davidlohr Bueso wrote:
> On Mon, 2012-09-03 at 12:11 +0300, Avi Kivity wrote:
>> On 09/03/2012 02:27 AM, Davidlohr Bueso wrote:
>> > On Fri, 2012-08-31 at 14:37 -0300, Marcelo Tosatti wrote:
>> >> On Fri, Aug 31, 2012 at 06:10:48PM +0200, Davidlohr Bueso wrote:
>> >> > For processors that support VPIDs we should invalidate the page table entry
>> >> > specified by the lineal address. For this purpose add support for individual
>> >> > address invalidations.
>> >>
>> >> Not necessary - a single context invalidation is performed through
>> >> KVM_REQ_TLB_FLUSH.
>> >
>> > Since vpid_sync_context() supports both single and all-context vpid
>> > invalidations, wouldn't it make sense to also add individual address
>> > ones as well, supporting further granularity?
>>
>> It might. Do you have benchmarks supporting this?
>>
>
> I ran two benchmarks: Java Dacapo[1] Sunflow (renders a set of images
> using ray tracing) and a vanilla 3.2 kernel build (with 1 job and -j8).
>
> The host configuration is an Intel i7-2635QM (4 cores + HT) with 4Gb RAM
> running Linus's latest and only running standard system daemons. For KVM
> I disabled EPT.
That's not very interesting. In all real machines, if you have VPID you
also have EPT. Intel are unlikely to produce a processor without EPT.
> The guest configuration is a 64bit 4 core 4Gb RAM, running Linux 3.2
> (debian) and only running the benchmark.
>
> All results represent the mean of 5 runs, with time(1).
The results are impressive, but lack real-world relevance.
Individual-address invalidation isn't very useful with EPT, since we let
the guest issue INVLPG itself and otherwise don't bother with guest page
tables.
Individual-address INVEPT would probably be more useful, but there is no
such instruction variant.
--
error compiling committee.c: too many arguments to function
^ permalink raw reply [flat|nested] 6+ messages in thread
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2012-08-31 16:10 [PATCH] KVM: VMX: invalidate vpid for invlpg instruction Davidlohr Bueso
2012-08-31 17:37 ` Marcelo Tosatti
2012-09-02 23:27 ` Davidlohr Bueso
2012-09-03 9:11 ` Avi Kivity
2012-09-05 21:54 ` Davidlohr Bueso
2012-09-06 8:05 ` Avi Kivity
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