| Message ID | 1310571145-28930-5-git-send-email-joerg.roedel@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 07/13/2011 06:32 PM, Joerg Roedel wrote: > From: Joerg Roedel<joro@8bytes.org> > > Move torwards emulation of VMCB-clean-bits by using a > seperate VMCB when running L2 guests. > > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index f81e35e..6dacf59 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -105,6 +105,8 @@ struct nested_state { > > /* Nested Paging related state */ > u64 nested_cr3; > + > + struct vmcb *n_vmcb; > }; > > #define MSRPM_OFFSETS 16 > @@ -974,6 +976,26 @@ static u64 svm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc) > return target_tsc - tsc; > } > > +static bool init_nested_vmcb(struct vcpu_svm *svm) > +{ > + struct vmcb_control_area *hc, *nc; > + > + svm->nested.n_vmcb = (void *)get_zeroed_page(GFP_KERNEL); > + if (svm->nested.n_vmcb == NULL) > + return false; > + > + nc =&svm->nested.n_vmcb->control; > + hc =&svm->host_vmcb->control; > + > + nc->iopm_base_pa = hc->iopm_base_pa; > + nc->msrpm_base_pa = hc->msrpm_base_pa; > + nc->nested_ctl = hc->nested_ctl; > + nc->pause_filter_count = hc->pause_filter_count; > + svm->nested.n_vmcb->save.g_pat = svm->host_vmcb->save.g_pat; > + > + return true; > +} > + Instead of initializing the non-nested vmcb and then copying it, separate out the bits you're copying here into a separate function (i.e. init_vmcb_host_state()) and call it for both vmcbs. I had practically the same comment for nvmx (see vmx_set_constant_host_state()).
On Thu, Jul 14, 2011 at 02:38:39PM +0300, Avi Kivity wrote: > On 07/13/2011 06:32 PM, Joerg Roedel wrote: >> +static bool init_nested_vmcb(struct vcpu_svm *svm) >> +{ >> + struct vmcb_control_area *hc, *nc; >> + >> + svm->nested.n_vmcb = (void *)get_zeroed_page(GFP_KERNEL); >> + if (svm->nested.n_vmcb == NULL) >> + return false; >> + >> + nc =&svm->nested.n_vmcb->control; >> + hc =&svm->host_vmcb->control; >> + >> + nc->iopm_base_pa = hc->iopm_base_pa; >> + nc->msrpm_base_pa = hc->msrpm_base_pa; >> + nc->nested_ctl = hc->nested_ctl; >> + nc->pause_filter_count = hc->pause_filter_count; >> + svm->nested.n_vmcb->save.g_pat = svm->host_vmcb->save.g_pat; >> + >> + return true; >> +} >> + > > Instead of initializing the non-nested vmcb and then copying it, > separate out the bits you're copying here into a separate function (i.e. > init_vmcb_host_state()) and call it for both vmcbs. > > I had practically the same comment for nvmx (see > vmx_set_constant_host_state()). Makes sense. I'll probably remove the lazy allocation and initialize both VMCBs at vcpu-creation time. The memory foodprint is the same as before because the hsave area was also allocated at the beginning. Joerg -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/14/2011 04:12 PM, Joerg Roedel wrote: > Makes sense. I'll probably remove the lazy allocation and initialize > both VMCBs at vcpu-creation time. The memory foodprint is the same as > before because the hsave area was also allocated at the beginning. Related, would we need a pool of n_vmcbs/vmcb02s? I guess the condition for reusing an n_vmcb would be: same vmcb_gpa and at least one clean bit set?
On Thu, Jul 14, 2011 at 04:26:39PM +0300, Avi Kivity wrote: > On 07/14/2011 04:12 PM, Joerg Roedel wrote: >> Makes sense. I'll probably remove the lazy allocation and initialize >> both VMCBs at vcpu-creation time. The memory foodprint is the same as >> before because the hsave area was also allocated at the beginning. > > Related, would we need a pool of n_vmcbs/vmcb02s? Probably. This depends on how nested-svm will be used I think. It is not very hard to add if really needed. Some kind of LRU is certainly needed too then. > I guess the condition for reusing an n_vmcb would be: same vmcb_gpa and > at least one clean bit set? Same vmcb_gpa is sufficient I think. I nothing is marked clean then it is the same situation as if the vmcb_gpa is different. Joerg -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/14/2011 04:40 PM, Joerg Roedel wrote: > On Thu, Jul 14, 2011 at 04:26:39PM +0300, Avi Kivity wrote: > > On 07/14/2011 04:12 PM, Joerg Roedel wrote: > >> Makes sense. I'll probably remove the lazy allocation and initialize > >> both VMCBs at vcpu-creation time. The memory foodprint is the same as > >> before because the hsave area was also allocated at the beginning. > > > > Related, would we need a pool of n_vmcbs/vmcb02s? > > Probably. This depends on how nested-svm will be used I think. It is not > very hard to add if really needed. Some kind of LRU is certainly needed > too then. > > > I guess the condition for reusing an n_vmcb would be: same vmcb_gpa and > > at least one clean bit set? > > Same vmcb_gpa is sufficient I think. I nothing is marked clean then it > is the same situation as if the vmcb_gpa is different. Agree with both.
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index f81e35e..6dacf59 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -105,6 +105,8 @@ struct nested_state { /* Nested Paging related state */ u64 nested_cr3; + + struct vmcb *n_vmcb; }; #define MSRPM_OFFSETS 16 @@ -974,6 +976,26 @@ static u64 svm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc) return target_tsc - tsc; } +static bool init_nested_vmcb(struct vcpu_svm *svm) +{ + struct vmcb_control_area *hc, *nc; + + svm->nested.n_vmcb = (void *)get_zeroed_page(GFP_KERNEL); + if (svm->nested.n_vmcb == NULL) + return false; + + nc = &svm->nested.n_vmcb->control; + hc = &svm->host_vmcb->control; + + nc->iopm_base_pa = hc->iopm_base_pa; + nc->msrpm_base_pa = hc->msrpm_base_pa; + nc->nested_ctl = hc->nested_ctl; + nc->pause_filter_count = hc->pause_filter_count; + svm->nested.n_vmcb->save.g_pat = svm->host_vmcb->save.g_pat; + + return true; +} + static void init_vmcb(struct vcpu_svm *svm) { struct vmcb_control_area *control = &svm->vmcb->control; @@ -1212,6 +1234,8 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); + if (svm->nested.n_vmcb != NULL) + __free_page(virt_to_page(svm->nested.n_vmcb)); __free_page(pfn_to_page(svm->vmcb_pa >> PAGE_SHIFT)); __free_pages(virt_to_page(svm->msrpm), MSRPM_ALLOC_ORDER); __free_page(virt_to_page(svm->nested.hsave)); @@ -2179,7 +2203,7 @@ static int nested_svm_vmexit(struct vcpu_svm *svm) { struct vmcb *nested_vmcb; struct vmcb *hsave = svm->nested.hsave; - struct vmcb *vmcb = svm->vmcb; + struct vmcb *vmcb = svm->nested.n_vmcb; struct page *page; trace_kvm_nested_vmexit_inject(vmcb->control.exit_code, @@ -2252,8 +2276,12 @@ static int nested_svm_vmexit(struct vcpu_svm *svm) if (!(svm->vcpu.arch.hflags & HF_VINTR_MASK)) nested_vmcb->control.int_ctl &= ~V_INTR_MASKING_MASK; + /* Switch VMCB back to host */ + svm->vmcb = svm->host_vmcb; + svm->vmcb_pa = __pa(svm->host_vmcb); + /* Restore the original control entries */ - copy_vmcb_control_area(vmcb, hsave); + copy_vmcb_control_area(svm->host_vmcb, hsave); kvm_clear_exception_queue(&svm->vcpu); kvm_clear_interrupt_queue(&svm->vcpu); @@ -2431,6 +2459,10 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm) nested_svm_init_mmu_context(&svm->vcpu); } + /* Switch VMCB */ + svm->vmcb = svm->nested.n_vmcb; + svm->vmcb_pa = __pa(svm->nested.n_vmcb); + /* Load the nested guest state */ svm->vmcb->save.es = nested_vmcb->save.es; svm->vmcb->save.cs = nested_vmcb->save.cs; @@ -2477,7 +2509,7 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm) svm->vmcb->control.lbr_ctl = nested_vmcb->control.lbr_ctl; svm->vmcb->control.int_vector = nested_vmcb->control.int_vector; svm->vmcb->control.int_state = nested_vmcb->control.int_state; - svm->vmcb->control.tsc_offset += nested_vmcb->control.tsc_offset; + svm->vmcb->control.tsc_offset = svm->host_vmcb->control.tsc_offset + nested_vmcb->control.tsc_offset; svm->vmcb->control.event_inj = nested_vmcb->control.event_inj; svm->vmcb->control.event_inj_err = nested_vmcb->control.event_inj_err; @@ -2566,6 +2598,11 @@ static int vmrun_interception(struct vcpu_svm *svm) if (nested_svm_check_permissions(svm)) return 1; + if (unlikely(svm->nested.n_vmcb == NULL)) { + if (!init_nested_vmcb(svm)) + goto failed; + } + /* Save rip after vmrun instruction */ kvm_rip_write(&svm->vcpu, kvm_rip_read(&svm->vcpu) + 3);