Hi Wanpeng,

On 07/07/2014 06:35 PM, Wanpeng Li wrote:
On Wed, Jul 02, 2014 at 05:00:37PM +0800, Tang Chen wrote:
apic access page is pinned in memory, and as a result it cannot be
migrated/hot-removed.

Actually it doesn't need to be pinned in memory.

This patch introduces a new vcpu request: KVM_REQ_MIGRATE_EPT. This requet

s/KVM_REQ_MIGRATE_EPT/KVM_REQ_MIGRATE_APIC

Thanks, will fix it in the next version.

Thanks.


will be made when kvm_mmu_notifier_invalidate_page() is called when the page
is unmapped from the qemu user space to reset APIC_ACCESS_ADDR pointer in
each online vcpu to 0. And will also be made when ept violation happens to
reset APIC_ACCESS_ADDR to the new page phys_addr (host phys_addr).
---
arch/x86/include/asm/kvm_host.h |  2 ++
arch/x86/kvm/mmu.c              | 15 +++++++++++++++
arch/x86/kvm/vmx.c              |  9 ++++++++-
arch/x86/kvm/x86.c              | 20 ++++++++++++++++++++
include/linux/kvm_host.h        |  1 +
virt/kvm/kvm_main.c             | 15 +++++++++++++++
6 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8771c0f..f104b87 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -575,6 +575,7 @@ struct kvm_arch {

        unsigned int tss_addr;
        struct page *apic_access_page;
+       bool apic_access_page_migrated;

        gpa_t wall_clock;

@@ -739,6 +740,7 @@ 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/mmu.c b/arch/x86/kvm/mmu.c
index c0d72f6..a655444 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3436,6 +3436,21 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t 
gpa, u32 error_code,
                kvm_make_request(KVM_REQ_MIGRATE_EPT, vcpu);
        }

+       if (gpa == VMX_APIC_ACCESS_PAGE_ADDR&&
+           vcpu->kvm->arch.apic_access_page_migrated) {
+               int i;
+
+               vcpu->kvm->arch.apic_access_page_migrated = false;
+
+               /*
+                * We need update APIC_ACCESS_ADDR pointer in each VMCS of
+                * all the online vcpus.
+                */
+               for (i = 0; i<  atomic_read(&vcpu->kvm->online_vcpus); i++)
+                       kvm_make_request(KVM_REQ_MIGRATE_APIC,
+                                        vcpu->kvm->vcpus[i]);
+       }
+
        spin_unlock(&vcpu->kvm->mmu_lock);

        return r;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c336cb3..abc152f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3988,7 +3988,7 @@ static int alloc_apic_access_page(struct kvm *kvm)
        if (r)
                goto out;

-       page = gfn_to_page(kvm, VMX_APIC_ACCESS_PAGE_ADDR>>  PAGE_SHIFT);
+       page = gfn_to_page_no_pin(kvm, VMX_APIC_ACCESS_PAGE_ADDR>>  PAGE_SHIFT);
        if (is_error_page(page)) {
                r = -EFAULT;
                goto out;
@@ -7075,6 +7075,12 @@ 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)
+{
+       if (vm_need_virtualize_apic_accesses(kvm))
+               vmcs_write64(APIC_ACCESS_ADDR, hpa);
+}
+
static void vmx_hwapic_isr_update(struct kvm *kvm, int isr)
{
        u16 status;
@@ -8846,6 +8852,7 @@ 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 a26524f..14e7174 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5943,6 +5943,24 @@ static void vcpu_migrated_page_update_ept(struct 
kvm_vcpu *vcpu)
        }
}

+static void vcpu_migrated_page_update_apic(struct kvm_vcpu *vcpu)
+{
+       struct kvm *kvm = vcpu->kvm;
+
+       if (kvm->arch.apic_access_page_migrated) {
+               if (kvm->arch.apic_access_page)
+                       kvm->arch.apic_access_page = pfn_to_page(0);
+               kvm_x86_ops->set_apic_access_page_addr(kvm, 0x0ull);
+       } else {
+               struct page *page;
+               page = gfn_to_page_no_pin(kvm,
+                               VMX_APIC_ACCESS_PAGE_ADDR>>  PAGE_SHIFT);
+               kvm->arch.apic_access_page = page;
+               kvm_x86_ops->set_apic_access_page_addr(kvm,
+                                                      page_to_phys(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
@@ -6005,6 +6023,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
                        vcpu_scan_ioapic(vcpu);
                if (kvm_check_request(KVM_REQ_MIGRATE_EPT, vcpu))
                        vcpu_migrated_page_update_ept(vcpu);
+               if (kvm_check_request(KVM_REQ_MIGRATE_APIC, vcpu))
+                       vcpu_migrated_page_update_apic(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 4b7e51a..e2ad65e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -137,6 +137,7 @@ static inline bool is_error_page(struct page *page)
#define KVM_REQ_ENABLE_IBS        23
#define KVM_REQ_DISABLE_IBS       24
#define KVM_REQ_MIGRATE_EPT       25
+#define KVM_REQ_MIGRATE_APIC      26

#define KVM_USERSPACE_IRQ_SOURCE_ID             0
#define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID        1
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d271e89..f06438c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -54,6 +54,7 @@
#include<asm/io.h>
#include<asm/uaccess.h>
#include<asm/pgtable.h>
+#include<asm/vmx.h>

#include "coalesced_mmio.h"
#include "async_pf.h"
@@ -300,6 +301,20 @@ static void kvm_mmu_notifier_invalidate_page(struct 
mmu_notifier *mn,
                kvm_make_request(KVM_REQ_MIGRATE_EPT, kvm->vcpus[0]);
        }

+       if (address ==
+           gfn_to_hva(kvm, VMX_APIC_ACCESS_PAGE_ADDR>>  PAGE_SHIFT)) {
+               int i;
+
+               kvm->arch.apic_access_page_migrated = true;
+
+               /*
+                * We need update APIC_ACCESS_ADDR pointer in each VMCS of
+                * all the online vcpus.
+                */
+               for (i = 0; i<  atomic_read(&kvm->online_vcpus); i++)
+                       kvm_make_request(KVM_REQ_MIGRATE_APIC, kvm->vcpus[i]);
+       }
+
        spin_unlock(&kvm->mmu_lock);
        srcu_read_unlock(&kvm->srcu, idx);
}
--
1.8.3.1

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