| Message ID | 1408621610-9665-2-git-send-email-wanpeng.li@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Il 21/08/2014 13:46, Wanpeng Li ha scritto: > This patch fix bug https://bugzilla.kernel.org/show_bug.cgi?id=61411 > > TPR shadow/threshold feature is important to speed up the Windows guest. > Besides, it is a must feature for certain VMM. > > We map virtual APIC page address and TPR threshold from L1 VMCS. If > TPR_BELOW_THRESHOLD VM exit is triggered by L2 guest and L1 interested > in, we inject it into L1 VMM for handling. > > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> > --- > v5 -> v6: > * fix bisect issue > v4 -> v5: > * moving the nested_vmx_failValid call inside the "if (!vmx->nested.virtual_apic_page)" > v3 -> v4: > * add Paolo's Reviewed-by > * unconditionally fail the vmentry, with a comment > * setup the TPR_SHADOW/virtual_apic_page of vmcs02 based on vmcs01 if L2 owns the APIC > v2 -> v3: > * nested vm entry failure if both tpr shadow and cr8 exiting bits are not set > v1 -> v2: > * don't take L0's "virtualize APIC accesses" setting into account > * virtual_apic_page do exactly the same thing that is done for apic_access_page > * add the tpr threshold field to the read-write fields for shadow VMCS > > arch/x86/kvm/vmx.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 48 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 24380a9..0eea49c 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -379,6 +379,7 @@ struct nested_vmx { > * we must keep them pinned while L2 runs. > */ > struct page *apic_access_page; > + struct page *virtual_apic_page; > u64 msr_ia32_feature_control; > > struct hrtimer preemption_timer; > @@ -533,6 +534,7 @@ static int max_shadow_read_only_fields = > ARRAY_SIZE(shadow_read_only_fields); > > static unsigned long shadow_read_write_fields[] = { > + TPR_THRESHOLD, > GUEST_RIP, > GUEST_RSP, > GUEST_CR0, > @@ -2330,7 +2332,7 @@ static __init void nested_vmx_setup_ctls_msrs(void) > CPU_BASED_MOV_DR_EXITING | CPU_BASED_UNCOND_IO_EXITING | > CPU_BASED_USE_IO_BITMAPS | CPU_BASED_MONITOR_EXITING | > CPU_BASED_RDPMC_EXITING | CPU_BASED_RDTSC_EXITING | > - CPU_BASED_PAUSE_EXITING | > + CPU_BASED_PAUSE_EXITING | CPU_BASED_TPR_SHADOW | > CPU_BASED_ACTIVATE_SECONDARY_CONTROLS; > /* > * We can allow some features even when not supported by the > @@ -6150,6 +6152,10 @@ static void free_nested(struct vcpu_vmx *vmx) > nested_release_page(vmx->nested.apic_access_page); > vmx->nested.apic_access_page = 0; > } > + if (vmx->nested.virtual_apic_page) { > + nested_release_page(vmx->nested.virtual_apic_page); > + vmx->nested.virtual_apic_page = 0; > + } > > nested_free_all_saved_vmcss(vmx); > } > @@ -6938,7 +6944,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu) > case EXIT_REASON_MCE_DURING_VMENTRY: > return 0; > case EXIT_REASON_TPR_BELOW_THRESHOLD: > - return 1; > + return nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW); > case EXIT_REASON_APIC_ACCESS: > return nested_cpu_has2(vmcs12, > SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES); > @@ -7059,6 +7065,12 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) > > static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr) > { > + struct vmcs12 *vmcs12 = get_vmcs12(vcpu); > + > + if (is_guest_mode(vcpu) && > + nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) > + return; > + > if (irr == -1 || tpr < irr) { > vmcs_write32(TPR_THRESHOLD, 0); > return; > @@ -7847,6 +7859,27 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu, > vmx->nested.apic_access_page = > nested_get_page(vcpu, vmcs12->apic_access_addr); > } > + > + if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) { Missing PAGE_ALIGNED check. I should have spotted this before, so I just fixed it and will commit the patch soon. Thanks for your persistence! Paolo > + if (vmx->nested.virtual_apic_page) /* shouldn't happen */ > + nested_release_page(vmx->nested.virtual_apic_page); > + vmx->nested.virtual_apic_page = > + nested_get_page(vcpu, vmcs12->virtual_apic_page_addr); > + > + /* > + * Failing the vm entry is _not_ what the processor does > + * but it's basically the only possibility we have. > + * We could still enter the guest if CR8 load exits are > + * enabled, CR8 store exits are enabled, and virtualize APIC > + * access is disabled; in this case the processor would never > + * use the TPR shadow and we could simply clear the bit from > + * the execution control. But such a configuration is useless, > + * so let's keep the code simple. > + */ > + if (!vmx->nested.virtual_apic_page) > + return false; > + } > + > return true; > } > > @@ -8040,6 +8073,15 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) > exec_control &= ~CPU_BASED_VIRTUAL_NMI_PENDING; > exec_control &= ~CPU_BASED_TPR_SHADOW; > exec_control |= vmcs12->cpu_based_vm_exec_control; > + > + if (exec_control & CPU_BASED_TPR_SHADOW) { > + vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, > + page_to_phys(vmx->nested.virtual_apic_page)); > + vmcs_write32(TPR_THRESHOLD, vmcs12->tpr_threshold); > + } else if (vm_need_tpr_shadow(vmx->vcpu.kvm)) > + vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, > + __pa(vmx->vcpu.arch.apic->regs)); > + > /* > * Merging of IO and MSR bitmaps not currently supported. > * Rather, exit every time. > @@ -8807,6 +8849,10 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, > nested_release_page(vmx->nested.apic_access_page); > vmx->nested.apic_access_page = 0; > } > + if (vmx->nested.virtual_apic_page) { > + nested_release_page(vmx->nested.virtual_apic_page); > + vmx->nested.virtual_apic_page = 0; > + } > > /* > * Exiting from L2 to L1, we're now back to L1 which thinks it just > -- 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
Hi Paolo, On Thu, Aug 21, 2014 at 02:33:36PM +0200, Paolo Bonzini wrote: [...] >> return; >> @@ -7847,6 +7859,27 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu, >> vmx->nested.apic_access_page = >> nested_get_page(vcpu, vmcs12->apic_access_addr); >> } >> + >> + if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) { > >Missing PAGE_ALIGNED check. I should have spotted this before, so I >just fixed it and will commit the patch soon. > Maybe I misunderstand your comments "On real hardware you could point the virtual-APIC page to an invalid address." http://lists.openwall.net/linux-kernel/2014/08/07/344 >Thanks for your persistence! > Thanks for your great help. ;-) Regards, Wanpeng Li >Paolo -- 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
Il 22/08/2014 01:30, Wanpeng Li ha scritto: > Maybe I misunderstand your comments "On real hardware you could point > the virtual-APIC page to an invalid address." > http://lists.openwall.net/linux-kernel/2014/08/07/344 > That referred to an address that doesn't correspond to RAM. You can use addresses like these in a real processor. But the manual says that "if the “use TPR shadow” VM-execution control is 1, VM entry ensures that the virtual-APIC address is 4-KByte aligned" (24.6.8 Controls For APIC Virtualization). This is the check that is missing. Paolo -- 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 Fri, Aug 22, 2014 at 10:36:07AM +0200, Paolo Bonzini wrote: >Il 22/08/2014 01:30, Wanpeng Li ha scritto: >> Maybe I misunderstand your comments "On real hardware you could point >> the virtual-APIC page to an invalid address." >> http://lists.openwall.net/linux-kernel/2014/08/07/344 >> > >That referred to an address that doesn't correspond to RAM. You can use >addresses like these in a real processor. > >But the manual says that "if the “use TPR shadow” VM-execution control >is 1, VM entry ensures that the virtual-APIC address is 4-KByte aligned" >(24.6.8 Controls For APIC Virtualization). This is the check that is >missing. Ok, thanks. Regards, Wanpeng Li > >Paolo -- 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
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 24380a9..0eea49c 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -379,6 +379,7 @@ struct nested_vmx { * we must keep them pinned while L2 runs. */ struct page *apic_access_page; + struct page *virtual_apic_page; u64 msr_ia32_feature_control; struct hrtimer preemption_timer; @@ -533,6 +534,7 @@ static int max_shadow_read_only_fields = ARRAY_SIZE(shadow_read_only_fields); static unsigned long shadow_read_write_fields[] = { + TPR_THRESHOLD, GUEST_RIP, GUEST_RSP, GUEST_CR0, @@ -2330,7 +2332,7 @@ static __init void nested_vmx_setup_ctls_msrs(void) CPU_BASED_MOV_DR_EXITING | CPU_BASED_UNCOND_IO_EXITING | CPU_BASED_USE_IO_BITMAPS | CPU_BASED_MONITOR_EXITING | CPU_BASED_RDPMC_EXITING | CPU_BASED_RDTSC_EXITING | - CPU_BASED_PAUSE_EXITING | + CPU_BASED_PAUSE_EXITING | CPU_BASED_TPR_SHADOW | CPU_BASED_ACTIVATE_SECONDARY_CONTROLS; /* * We can allow some features even when not supported by the @@ -6150,6 +6152,10 @@ static void free_nested(struct vcpu_vmx *vmx) nested_release_page(vmx->nested.apic_access_page); vmx->nested.apic_access_page = 0; } + if (vmx->nested.virtual_apic_page) { + nested_release_page(vmx->nested.virtual_apic_page); + vmx->nested.virtual_apic_page = 0; + } nested_free_all_saved_vmcss(vmx); } @@ -6938,7 +6944,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu) case EXIT_REASON_MCE_DURING_VMENTRY: return 0; case EXIT_REASON_TPR_BELOW_THRESHOLD: - return 1; + return nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW); case EXIT_REASON_APIC_ACCESS: return nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES); @@ -7059,6 +7065,12 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr) { + struct vmcs12 *vmcs12 = get_vmcs12(vcpu); + + if (is_guest_mode(vcpu) && + nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) + return; + if (irr == -1 || tpr < irr) { vmcs_write32(TPR_THRESHOLD, 0); return; @@ -7847,6 +7859,27 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu, vmx->nested.apic_access_page = nested_get_page(vcpu, vmcs12->apic_access_addr); } + + if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) { + if (vmx->nested.virtual_apic_page) /* shouldn't happen */ + nested_release_page(vmx->nested.virtual_apic_page); + vmx->nested.virtual_apic_page = + nested_get_page(vcpu, vmcs12->virtual_apic_page_addr); + + /* + * Failing the vm entry is _not_ what the processor does + * but it's basically the only possibility we have. + * We could still enter the guest if CR8 load exits are + * enabled, CR8 store exits are enabled, and virtualize APIC + * access is disabled; in this case the processor would never + * use the TPR shadow and we could simply clear the bit from + * the execution control. But such a configuration is useless, + * so let's keep the code simple. + */ + if (!vmx->nested.virtual_apic_page) + return false; + } + return true; } @@ -8040,6 +8073,15 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) exec_control &= ~CPU_BASED_VIRTUAL_NMI_PENDING; exec_control &= ~CPU_BASED_TPR_SHADOW; exec_control |= vmcs12->cpu_based_vm_exec_control; + + if (exec_control & CPU_BASED_TPR_SHADOW) { + vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, + page_to_phys(vmx->nested.virtual_apic_page)); + vmcs_write32(TPR_THRESHOLD, vmcs12->tpr_threshold); + } else if (vm_need_tpr_shadow(vmx->vcpu.kvm)) + vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, + __pa(vmx->vcpu.arch.apic->regs)); + /* * Merging of IO and MSR bitmaps not currently supported. * Rather, exit every time. @@ -8807,6 +8849,10 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, nested_release_page(vmx->nested.apic_access_page); vmx->nested.apic_access_page = 0; } + if (vmx->nested.virtual_apic_page) { + nested_release_page(vmx->nested.virtual_apic_page); + vmx->nested.virtual_apic_page = 0; + } /* * Exiting from L2 to L1, we're now back to L1 which thinks it just