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| author |   Hollis Blanchard <hollisb@us.ibm.com> | 2008-07-25 13:54:51 -0500 |
|---|---|---|
| committer |   Avi Kivity <avi@qumranet.com> | 2008-10-15 10:15:16 +0200 |
| commit | 20754c2495a791b5b429c0da63394c86ade978e7 (patch) | |
| tree | fbeed7fdab0f91417798aa5e4cea22f15a255275 /arch/powerpc/kvm/booke_interrupts.S | |
| parent | KVM: ppc: guest breakpoint support (diff) | |
| download | linux-dev-20754c2495a791b5b429c0da63394c86ade978e7.tar.xz linux-dev-20754c2495a791b5b429c0da63394c86ade978e7.zip | |
KVM: ppc: Stop saving host TLB state
We're saving the host TLB state to memory on every exit, but never using it.
Originally I had thought that we'd want to restore host TLB for heavyweight
exits, but that could actually hurt when context switching to an unrelated host
process (i.e. not qemu).
Since this decreases the performance penalty of all exits, this patch improves
guest boot time by about 15%.
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/powerpc/kvm/booke_interrupts.S')
| -rw-r--r-- | arch/powerpc/kvm/booke_interrupts.S | 17 |
1 files changed, 3 insertions, 14 deletions
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S index 8eaba2613ffd..3e88dfa1dbe4 100644 --- a/arch/powerpc/kvm/booke_interrupts.S +++ b/arch/powerpc/kvm/booke_interrupts.S @@ -342,26 +342,15 @@ lightweight_exit: andc r6, r5, r6 mtmsr r6 - /* Save the host's non-pinned TLB mappings, and load the guest mappings - * over them. Leave the host's "pinned" kernel mappings in place. */ - /* XXX optimization: use generation count to avoid swapping unmodified - * entries. */ + /* Load the guest mappings, leaving the host's "pinned" kernel mappings + * in place. */ + /* XXX optimization: load only modified guest entries. */ mfspr r10, SPRN_MMUCR /* Save host MMUCR. */ lis r8, tlb_44x_hwater@ha lwz r8, tlb_44x_hwater@l(r8) - addi r3, r4, VCPU_HOST_TLB - 4 addi r9, r4, VCPU_SHADOW_TLB - 4 li r6, 0 1: - /* Save host entry. */ - tlbre r7, r6, PPC44x_TLB_PAGEID - mfspr r5, SPRN_MMUCR - stwu r5, 4(r3) - stwu r7, 4(r3) - tlbre r7, r6, PPC44x_TLB_XLAT - stwu r7, 4(r3) - tlbre r7, r6, PPC44x_TLB_ATTRIB - stwu r7, 4(r3) /* Load guest entry. */ lwzu r7, 4(r9) mtspr SPRN_MMUCR, r7 |