KVM: async_pf: Provide additional direct page notification

By setting a Kconfig option, the architecture can control when
guest notifications will be presented by the apf backend.
There is the default batch mechanism, working as before, where the vcpu
thread should pull in this information.
Opposite to this, there is now the direct mechanism, that will push the
information to the guest.
This way s390 can use an already existing architecture interface.

Still the vcpu thread should call check_completion to cleanup leftovers.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
(cherry picked from commit e0ead41a6dac09f86675ce07a66e4b253a9b7bd5)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 3c1877bbfe6a1481d02a65096fb17bceb50a5c12..f47d2e11108e485d84c586c59915eb066a39430a 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3232,7 +3232,7 @@ static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn)
        arch.direct_map = vcpu->arch.mmu.direct_map;
        arch.cr3 = vcpu->arch.mmu.get_cr3(vcpu);
 
-       return kvm_setup_async_pf(vcpu, gva, gfn, &arch);
+       return kvm_setup_async_pf(vcpu, gva, gfn_to_hva(vcpu->kvm, gfn), &arch);
 }
 
 static bool can_do_async_pf(struct kvm_vcpu *vcpu)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 95625d5cb3f0a0273337e7d4c2ea3e8254daf0d4..f6801d10e04ca2c1a1583f02380ed475a6b5c784 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -180,7 +180,7 @@ struct kvm_async_pf {
 
 void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu);
 void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu);
-int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
+int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
                       struct kvm_arch_async_pf *arch);
 int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu);
 #endif

diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index fbe1a48bd6292b575d349eced2d0628d9082b1db..13f2d19793e3e65986466c90c483f84249c71cd9 100644 (file)
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -22,6 +22,10 @@ config KVM_MMIO
 config KVM_ASYNC_PF
        bool
 
+# Toggle to switch between direct notification and batch job
+config KVM_ASYNC_PF_SYNC
+       bool
+
 config HAVE_KVM_MSI
        bool
 

diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 8631d9c14320bea69b4e9713013ab54b2e3752be..00980ab02c4533a2adfb6cd434365b869f432be0 100644 (file)
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -28,6 +28,21 @@
 #include "async_pf.h"
 #include <trace/events/kvm.h>
 
+static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu,
+                                              struct kvm_async_pf *work)
+{
+#ifdef CONFIG_KVM_ASYNC_PF_SYNC
+       kvm_arch_async_page_present(vcpu, work);
+#endif
+}
+static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu,
+                                               struct kvm_async_pf *work)
+{
+#ifndef CONFIG_KVM_ASYNC_PF_SYNC
+       kvm_arch_async_page_present(vcpu, work);
+#endif
+}
+
 static struct kmem_cache *async_pf_cache;
 
 int kvm_async_pf_init(void)
@@ -69,6 +84,7 @@ static void async_pf_execute(struct work_struct *work)
        down_read(&mm->mmap_sem);
        get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);
        up_read(&mm->mmap_sem);
+       kvm_async_page_present_sync(vcpu, apf);
        unuse_mm(mm);
 
        spin_lock(&vcpu->async_pf.lock);
@@ -138,7 +154,7 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
        }
 }
 
-int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
+int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
                       struct kvm_arch_async_pf *arch)
 {
        struct kvm_async_pf *work;
@@ -159,7 +175,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
        work->wakeup_all = false;
        work->vcpu = vcpu;
        work->gva = gva;
-       work->addr = gfn_to_hva(vcpu->kvm, gfn);
+       work->addr = hva;
        work->arch = *arch;
        work->mm = current->mm;
        atomic_inc(&work->mm->mm_count);