diff mbox

[v6,4/6] kvm, mem-hotplug: Reload L1' apic access page on migration in vcpu_enter_guest().

Message ID 1410864122-12434-5-git-send-email-tangchen@cn.fujitsu.com (mailing list archive)
State New, archived
Headers show

Commit Message

tangchen Sept. 16, 2014, 10:42 a.m. UTC
apic access page is pinned in memory. As a result, it cannot be migrated/hot-removed.
Actually, it is not necessary to be pinned.

The hpa of apic access page is stored in VMCS APIC_ACCESS_ADDR pointer. When
the page is migrated, kvm_mmu_notifier_invalidate_page() will invalidate the
corresponding ept entry. This patch introduces a new vcpu request named
KVM_REQ_APIC_PAGE_RELOAD, and makes this request to all the vcpus at this time,
and force all the vcpus exit guest, and re-enter guest till they updates the VMCS
APIC_ACCESS_ADDR pointer to the new apic access page address, and updates
kvm->arch.apic_access_page to the new page.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/svm.c              |  6 ++++++
 arch/x86/kvm/vmx.c              |  6 ++++++
 arch/x86/kvm/x86.c              | 15 +++++++++++++++
 include/linux/kvm_host.h        |  2 ++
 virt/kvm/kvm_main.c             | 12 ++++++++++++
 6 files changed, 42 insertions(+)

Comments

Paolo Bonzini Sept. 16, 2014, 11:24 a.m. UTC | #1
Il 16/09/2014 12:42, Tang Chen ha scritto:
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 33712fb..0df82c1 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -210,6 +210,11 @@ void kvm_make_scan_ioapic_request(struct kvm *kvm)
>  	make_all_cpus_request(kvm, KVM_REQ_SCAN_IOAPIC);
>  }
>  
> +void kvm_reload_apic_access_page(struct kvm *kvm)
> +{
> +	make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
> +}
> +
>  int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
>  {
>  	struct page *page;
> @@ -294,6 +299,13 @@ static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn,
>  	if (need_tlb_flush)
>  		kvm_flush_remote_tlbs(kvm);
>  
> +	/*
> +	 * The physical address of apic access page is stored in VMCS.
> +	 * Update it when it becomes invalid.
> +	 */
> +	if (address == gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT))
> +		kvm_reload_apic_access_page(kvm);

This cannot be in the generic code.  It is architecture-specific.
Please add a new function kvm_arch_mmu_notifier_invalidate_page, and
call it outside the mmu_lock.

kvm_reload_apic_access_page need not be in virt/kvm/kvm_main.c, either.

Paolo

>  	spin_unlock(&kvm->mmu_lock);
>  	srcu_read_unlock(&kvm->srcu, idx);
>  }

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tangchen Sept. 17, 2014, 8:13 a.m. UTC | #2
On 09/16/2014 07:24 PM, Paolo Bonzini wrote:
> Il 16/09/2014 12:42, Tang Chen ha scritto:
>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>> index 33712fb..0df82c1 100644
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -210,6 +210,11 @@ void kvm_make_scan_ioapic_request(struct kvm *kvm)
>>   	make_all_cpus_request(kvm, KVM_REQ_SCAN_IOAPIC);
>>   }
>>   
>> +void kvm_reload_apic_access_page(struct kvm *kvm)
>> +{
>> +	make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
>> +}
>> +
>>   int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
>>   {
>>   	struct page *page;
>> @@ -294,6 +299,13 @@ static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn,
>>   	if (need_tlb_flush)
>>   		kvm_flush_remote_tlbs(kvm);
>>   
>> +	/*
>> +	 * The physical address of apic access page is stored in VMCS.
>> +	 * Update it when it becomes invalid.
>> +	 */
>> +	if (address == gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT))
>> +		kvm_reload_apic_access_page(kvm);
> This cannot be in the generic code.  It is architecture-specific.

Yes.

> Please add a new function kvm_arch_mmu_notifier_invalidate_page, and
> call it outside the mmu_lock.

Then I think we need a macro to control the calling of this arch function
since other architectures do not have it.

>
> kvm_reload_apic_access_page need not be in virt/kvm/kvm_main.c, either.

Since kvm_reload_apic_access_page() only calls make_all_cpus_request(),
and make_all_cpus_request() is static, I'd like to make it non-static, 
rename
it to kvm_make_all_cpus_request() and call it directly in 
kvm_arch_mmu_notifier_invalidate_page().
we don't need kvm_reload_apic_access_page() actually.

Thanks.

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Paolo Bonzini Sept. 17, 2014, 9:14 a.m. UTC | #3
Il 17/09/2014 10:13, Tang Chen ha scritto:
> 
> 
>> Please add a new function kvm_arch_mmu_notifier_invalidate_page, and
>> call it outside the mmu_lock.
> 
> Then I think we need a macro to control the calling of this arch function
> since other architectures do not have it.

You can add an inline function that does nothing.  There are other examples.

>> kvm_reload_apic_access_page need not be in virt/kvm/kvm_main.c, either.
> 
> Since kvm_reload_apic_access_page() only calls make_all_cpus_request(),
> and make_all_cpus_request() is static, I'd like to make it non-static, rename
> it to kvm_make_all_cpus_request() and call it directly in kvm_arch_mmu_notifier_invalidate_page().
> we don't need kvm_reload_apic_access_page() actually.

Ok.

Paolo
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diff mbox

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 35171c7..514183e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -739,6 +739,7 @@  struct kvm_x86_ops {
 	void (*hwapic_isr_update)(struct kvm *kvm, int isr);
 	void (*load_eoi_exitmap)(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
 	void (*set_virtual_x2apic_mode)(struct kvm_vcpu *vcpu, bool set);
+	void (*set_apic_access_page_addr)(struct kvm *kvm, hpa_t hpa);
 	void (*deliver_posted_interrupt)(struct kvm_vcpu *vcpu, int vector);
 	void (*sync_pir_to_irr)(struct kvm_vcpu *vcpu);
 	int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1d941ad..f2eacc4 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3619,6 +3619,11 @@  static void svm_set_virtual_x2apic_mode(struct kvm_vcpu *vcpu, bool set)
 	return;
 }
 
+static void svm_set_apic_access_page_addr(struct kvm *kvm, hpa_t hpa)
+{
+	return;
+}
+
 static int svm_vm_has_apicv(struct kvm *kvm)
 {
 	return 0;
@@ -4373,6 +4378,7 @@  static struct kvm_x86_ops svm_x86_ops = {
 	.enable_irq_window = enable_irq_window,
 	.update_cr8_intercept = update_cr8_intercept,
 	.set_virtual_x2apic_mode = svm_set_virtual_x2apic_mode,
+	.set_apic_access_page_addr = svm_set_apic_access_page_addr,
 	.vm_has_apicv = svm_vm_has_apicv,
 	.load_eoi_exitmap = svm_load_eoi_exitmap,
 	.hwapic_isr_update = svm_hwapic_isr_update,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 72a0470..a1a9797 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7090,6 +7090,11 @@  static void vmx_set_virtual_x2apic_mode(struct kvm_vcpu *vcpu, bool set)
 	vmx_set_msr_bitmap(vcpu);
 }
 
+static void vmx_set_apic_access_page_addr(struct kvm *kvm, hpa_t hpa)
+{
+	vmcs_write64(APIC_ACCESS_ADDR, hpa);
+}
+
 static void vmx_hwapic_isr_update(struct kvm *kvm, int isr)
 {
 	u16 status;
@@ -8909,6 +8914,7 @@  static struct kvm_x86_ops vmx_x86_ops = {
 	.enable_irq_window = enable_irq_window,
 	.update_cr8_intercept = update_cr8_intercept,
 	.set_virtual_x2apic_mode = vmx_set_virtual_x2apic_mode,
+	.set_apic_access_page_addr = vmx_set_apic_access_page_addr,
 	.vm_has_apicv = vmx_vm_has_apicv,
 	.load_eoi_exitmap = vmx_load_eoi_exitmap,
 	.hwapic_irr_update = vmx_hwapic_irr_update,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e05bd58..27c3d30 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5989,6 +5989,19 @@  static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
 	kvm_apic_update_tmr(vcpu, tmr);
 }
 
+static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * apic access page could be migrated. When the page is being migrated,
+	 * GUP will wait till the migrate entry is replaced with the new pte
+	 * entry pointing to the new page.
+	 */
+	vcpu->kvm->arch.apic_access_page = gfn_to_page(vcpu->kvm,
+				APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
+	kvm_x86_ops->set_apic_access_page_addr(vcpu->kvm,
+				page_to_phys(vcpu->kvm->arch.apic_access_page));
+}
+
 /*
  * Returns 1 to let __vcpu_run() continue the guest execution loop without
  * exiting to the userspace.  Otherwise, the value will be returned to the
@@ -6049,6 +6062,8 @@  static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 			kvm_deliver_pmi(vcpu);
 		if (kvm_check_request(KVM_REQ_SCAN_IOAPIC, vcpu))
 			vcpu_scan_ioapic(vcpu);
+		if (kvm_check_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu))
+			kvm_vcpu_reload_apic_access_page(vcpu);
 	}
 
 	if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index a4c33b3..8be076a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -136,6 +136,7 @@  static inline bool is_error_page(struct page *page)
 #define KVM_REQ_GLOBAL_CLOCK_UPDATE 22
 #define KVM_REQ_ENABLE_IBS        23
 #define KVM_REQ_DISABLE_IBS       24
+#define KVM_REQ_APIC_PAGE_RELOAD  25
 
 #define KVM_USERSPACE_IRQ_SOURCE_ID		0
 #define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID	1
@@ -579,6 +580,7 @@  void kvm_flush_remote_tlbs(struct kvm *kvm);
 void kvm_reload_remote_mmus(struct kvm *kvm);
 void kvm_make_mclock_inprogress_request(struct kvm *kvm);
 void kvm_make_scan_ioapic_request(struct kvm *kvm);
+void kvm_reload_apic_access_page(struct kvm *kvm);
 
 long kvm_arch_dev_ioctl(struct file *filp,
 			unsigned int ioctl, unsigned long arg);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 33712fb..0df82c1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -210,6 +210,11 @@  void kvm_make_scan_ioapic_request(struct kvm *kvm)
 	make_all_cpus_request(kvm, KVM_REQ_SCAN_IOAPIC);
 }
 
+void kvm_reload_apic_access_page(struct kvm *kvm)
+{
+	make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
+}
+
 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
 	struct page *page;
@@ -294,6 +299,13 @@  static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn,
 	if (need_tlb_flush)
 		kvm_flush_remote_tlbs(kvm);
 
+	/*
+	 * The physical address of apic access page is stored in VMCS.
+	 * Update it when it becomes invalid.
+	 */
+	if (address == gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT))
+		kvm_reload_apic_access_page(kvm);
+
 	spin_unlock(&kvm->mmu_lock);
 	srcu_read_unlock(&kvm->srcu, idx);
 }