kvm: Add interruptible flag to __gfn_to_pfn_memslot()

Add a new "interruptible" flag showing that the caller is willing to be
interrupted by signals during the __gfn_to_pfn_memslot() request.  Wire it
up with a FOLL_INTERRUPTIBLE flag that we've just introduced.

This prepares KVM to be able to respond to SIGUSR1 (for QEMU that's the
SIGIPI) even during e.g. handling an userfaultfd page fault.

No functional change intended.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221011195809.557016-4-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 60ee3d9..f154d4a 100644 (file)
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1239,7 +1239,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
         */
        smp_rmb();
 
-       pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
+       pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL,
                                   write_fault, &writable, NULL);
        if (pfn == KVM_PFN_ERR_HWPOISON) {
                kvm_send_hwpoison_signal(hva, vma_shift);

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index e9744b4..4939f57 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -598,7 +598,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
                write_ok = true;
        } else {
                /* Call KVM generic code to do the slow-path check */
-               pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
+               pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL,
                                           writing, &write_ok, NULL);
                if (is_error_noslot_pfn(pfn))
                        return -EFAULT;

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 5d5e12f..9d3743c 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -846,7 +846,7 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
                unsigned long pfn;
 
                /* Call KVM generic code to do the slow-path check */
-               pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
+               pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL,
                                           writing, upgrade_p, NULL);
                if (is_error_noslot_pfn(pfn))
                        return -EFAULT;

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f8c92a4..0bbfb33 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4170,7 +4170,7 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
        }
 
        async = false;
-       fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, &async,
+       fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, false, &async,
                                          fault->write, &fault->map_writable,
                                          &fault->hva);
        if (!async)
@@ -4187,7 +4187,7 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
                }
        }
 
-       fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, NULL,
+       fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, false, NULL,
                                          fault->write, &fault->map_writable,
                                          &fault->hva);
        return RET_PF_CONTINUE;

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 911b064..8fe4665 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1150,8 +1150,8 @@ kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
 kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn);
 kvm_pfn_t gfn_to_pfn_memslot_atomic(const struct kvm_memory_slot *slot, gfn_t gfn);
 kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
-                              bool atomic, bool *async, bool write_fault,
-                              bool *writable, hva_t *hva);
+                              bool atomic, bool interruptible, bool *async,
+                              bool write_fault, bool *writable, hva_t *hva);
 
 void kvm_release_pfn_clean(kvm_pfn_t pfn);
 void kvm_release_pfn_dirty(kvm_pfn_t pfn);

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 558f52d..43bbe4f 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2514,7 +2514,7 @@ static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
  * 1 indicates success, -errno is returned if error is detected.
  */
 static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
-                          bool *writable, kvm_pfn_t *pfn)
+                          bool interruptible, bool *writable, kvm_pfn_t *pfn)
 {
        unsigned int flags = FOLL_HWPOISON;
        struct page *page;
@@ -2529,6 +2529,8 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
                flags |= FOLL_WRITE;
        if (async)
                flags |= FOLL_NOWAIT;
+       if (interruptible)
+               flags |= FOLL_INTERRUPTIBLE;
 
        npages = get_user_pages_unlocked(addr, 1, &page, flags);
        if (npages != 1)
@@ -2638,6 +2640,7 @@ out:
  * Pin guest page in memory and return its pfn.
  * @addr: host virtual address which maps memory to the guest
  * @atomic: whether this function can sleep
+ * @interruptible: whether the process can be interrupted by non-fatal signals
  * @async: whether this function need to wait IO complete if the
  *         host page is not in the memory
  * @write_fault: whether we should get a writable host page
@@ -2648,8 +2651,8 @@ out:
  * 2): @write_fault = false && @writable, @writable will tell the caller
  *     whether the mapping is writable.
  */
-kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
-                    bool write_fault, bool *writable)
+kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible,
+                    bool *async, bool write_fault, bool *writable)
 {
        struct vm_area_struct *vma;
        kvm_pfn_t pfn;
@@ -2664,7 +2667,8 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
        if (atomic)
                return KVM_PFN_ERR_FAULT;
 
-       npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
+       npages = hva_to_pfn_slow(addr, async, write_fault, interruptible,
+                                writable, &pfn);
        if (npages == 1)
                return pfn;
        if (npages == -EINTR)
@@ -2699,8 +2703,8 @@ exit:
 }
 
 kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
-                              bool atomic, bool *async, bool write_fault,
-                              bool *writable, hva_t *hva)
+                              bool atomic, bool interruptible, bool *async,
+                              bool write_fault, bool *writable, hva_t *hva)
 {
        unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
 
@@ -2725,7 +2729,7 @@ kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
                writable = NULL;
        }
 
-       return hva_to_pfn(addr, atomic, async, write_fault,
+       return hva_to_pfn(addr, atomic, interruptible, async, write_fault,
                          writable);
 }
 EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
@@ -2733,20 +2737,22 @@ EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
 kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
                      bool *writable)
 {
-       return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, NULL,
-                                   write_fault, writable, NULL);
+       return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, false,
+                                   NULL, write_fault, writable, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
 
 kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn)
 {
-       return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL, NULL);
+       return __gfn_to_pfn_memslot(slot, gfn, false, false, NULL, true,
+                                   NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
 
 kvm_pfn_t gfn_to_pfn_memslot_atomic(const struct kvm_memory_slot *slot, gfn_t gfn)
 {
-       return __gfn_to_pfn_memslot(slot, gfn, true, NULL, true, NULL, NULL);
+       return __gfn_to_pfn_memslot(slot, gfn, true, false, NULL, true,
+                                   NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
 

diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h
index 41da467..a1ab150 100644 (file)
--- a/virt/kvm/kvm_mm.h
+++ b/virt/kvm/kvm_mm.h
@@ -24,8 +24,8 @@
 #define KVM_MMU_READ_UNLOCK(kvm)       spin_unlock(&(kvm)->mmu_lock)
 #endif /* KVM_HAVE_MMU_RWLOCK */
 
-kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
-                    bool write_fault, bool *writable);
+kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible,
+                    bool *async, bool write_fault, bool *writable);
 
 #ifdef CONFIG_HAVE_KVM_PFNCACHE
 void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm,

diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index 346e47f..bd4a46a 100644 (file)
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -185,7 +185,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
                }
 
                /* We always request a writeable mapping */
-               new_pfn = hva_to_pfn(gpc->uhva, false, NULL, true, NULL);
+               new_pfn = hva_to_pfn(gpc->uhva, false, false, NULL, true, NULL);
                if (is_error_noslot_pfn(new_pfn))
                        goto out_error;