KVM: PPC: Book3S HV: Handle memory slot deletion and modification correctly

This adds an implementation of kvm_arch_flush_shadow_memslot for
Book3S HV, and arranges for kvmppc_core_commit_memory_region to
flush the dirty log when modifying an existing slot.  With this,
we can handle deletion and modification of memory slots.

kvm_arch_flush_shadow_memslot calls kvmppc_core_flush_memslot, which
on Book3S HV now traverses the reverse map chains to remove any HPT
(hashed page table) entries referring to pages in the memslot.  This
gets called by generic code whenever deleting a memslot or changing
the guest physical address for a memslot.

We flush the dirty log in kvmppc_core_commit_memory_region for
consistency with what x86 does.  We only need to flush when an
existing memslot is being modified, because for a new memslot the
rmap array (which stores the dirty bits) is all zero, meaning that
every page is considered clean already, and when deleting a memslot
we obviously don't care about the dirty bits any more.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index f0e0c6a66d973fdb833138e2433b54be860dc4f3..ab738005d2eafc57b6bb8bf5661cab3f05502f2f 100644 (file)
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -160,7 +160,7 @@ extern long kvmppc_virtmode_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
 extern long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
                        long pte_index, unsigned long pteh, unsigned long ptel);
 extern long kvmppc_hv_get_dirty_log(struct kvm *kvm,
-                       struct kvm_memory_slot *memslot);
+                       struct kvm_memory_slot *memslot, unsigned long *map);
 
 extern void kvmppc_entry_trampoline(void);
 extern void kvmppc_hv_entry_trampoline(void);

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 41a00eae68c72a5a890b4297ff1ab5072a39db91..3fb980d293e584f30ceb2a41b7b279ac7f4b0947 100644 (file)
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -151,9 +151,12 @@ extern int kvmppc_core_prepare_memory_region(struct kvm *kvm,
                                struct kvm_memory_slot *memslot,
                                struct kvm_userspace_memory_region *mem);
 extern void kvmppc_core_commit_memory_region(struct kvm *kvm,
-                               struct kvm_userspace_memory_region *mem);
+                               struct kvm_userspace_memory_region *mem,
+                               struct kvm_memory_slot old);
 extern int kvm_vm_ioctl_get_smmu_info(struct kvm *kvm,
                                      struct kvm_ppc_smmu_info *info);
+extern void kvmppc_core_flush_memslot(struct kvm *kvm,
+                                     struct kvm_memory_slot *memslot);
 
 extern int kvmppc_bookehv_init(void);
 extern void kvmppc_bookehv_exit(void);

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index a389cc62b16c7103541d3936e1893af7a1472ab4..f598366e51c648a5bbb336a5359da251487e24c2 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -851,7 +851,8 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
                psize = hpte_page_size(hptep[0], ptel);
                if ((hptep[0] & HPTE_V_VALID) &&
                    hpte_rpn(ptel, psize) == gfn) {
-                       hptep[0] |= HPTE_V_ABSENT;
+                       if (kvm->arch.using_mmu_notifiers)
+                               hptep[0] |= HPTE_V_ABSENT;
                        kvmppc_invalidate_hpte(kvm, hptep, i);
                        /* Harvest R and C */
                        rcbits = hptep[1] & (HPTE_R_R | HPTE_R_C);
@@ -878,6 +879,28 @@ int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
        return 0;
 }
 
+void kvmppc_core_flush_memslot(struct kvm *kvm, struct kvm_memory_slot *memslot)
+{
+       unsigned long *rmapp;
+       unsigned long gfn;
+       unsigned long n;
+
+       rmapp = memslot->arch.rmap;
+       gfn = memslot->base_gfn;
+       for (n = memslot->npages; n; --n) {
+               /*
+                * Testing the present bit without locking is OK because
+                * the memslot has been marked invalid already, and hence
+                * no new HPTEs referencing this page can be created,
+                * thus the present bit can't go from 0 to 1.
+                */
+               if (*rmapp & KVMPPC_RMAP_PRESENT)
+                       kvm_unmap_rmapp(kvm, rmapp, gfn);
+               ++rmapp;
+               ++gfn;
+       }
+}
+
 static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
                         unsigned long gfn)
 {
@@ -1031,16 +1054,16 @@ static int kvm_test_clear_dirty(struct kvm *kvm, unsigned long *rmapp)
        return ret;
 }
 
-long kvmppc_hv_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
+long kvmppc_hv_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot,
+                            unsigned long *map)
 {
        unsigned long i;
-       unsigned long *rmapp, *map;
+       unsigned long *rmapp;
 
        preempt_disable();
        rmapp = memslot->arch.rmap;
-       map = memslot->dirty_bitmap;
        for (i = 0; i < memslot->npages; ++i) {
-               if (kvm_test_clear_dirty(kvm, rmapp))
+               if (kvm_test_clear_dirty(kvm, rmapp) && map)
                        __set_bit_le(i, map);
                ++rmapp;
        }

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 817837de7362d0d0faa592d914d482936b0453c0..38c7f1bc3495c7b7d19f92e8d5b04434ea07131b 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1288,7 +1288,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
        n = kvm_dirty_bitmap_bytes(memslot);
        memset(memslot->dirty_bitmap, 0, n);
 
-       r = kvmppc_hv_get_dirty_log(kvm, memslot);
+       r = kvmppc_hv_get_dirty_log(kvm, memslot, memslot->dirty_bitmap);
        if (r)
                goto out;
 
@@ -1378,8 +1378,22 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 }
 
 void kvmppc_core_commit_memory_region(struct kvm *kvm,
-                               struct kvm_userspace_memory_region *mem)
+                                     struct kvm_userspace_memory_region *mem,
+                                     struct kvm_memory_slot old)
 {
+       unsigned long npages = mem->memory_size >> PAGE_SHIFT;
+       struct kvm_memory_slot *memslot;
+
+       if (npages && old.npages) {
+               /*
+                * If modifying a memslot, reset all the rmap dirty bits.
+                * If this is a new memslot, we don't need to do anything
+                * since the rmap array starts out as all zeroes,
+                * i.e. no pages are dirty.
+                */
+               memslot = id_to_memslot(kvm->memslots, mem->slot);
+               kvmppc_hv_get_dirty_log(kvm, memslot, NULL);
+       }
 }
 
 static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)

diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 63eb94e63cc3a383d28528dfe82df877a78893d5..9955216477a4c7934284276b499184893e959251 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -81,7 +81,7 @@ static void remove_revmap_chain(struct kvm *kvm, long pte_index,
        ptel = rev->guest_rpte |= rcbits;
        gfn = hpte_rpn(ptel, hpte_page_size(hpte_v, ptel));
        memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
-       if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
+       if (!memslot)
                return;
 
        rmap = real_vmalloc_addr(&memslot->arch.rmap[gfn - memslot->base_gfn]);

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index fdadc9e57da2d9a720dbf31dad356acc28e4f353..4d0667a810a46b6f58cfc0d3a64830b2e5bc3909 100644 (file)
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -1239,7 +1239,12 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 }
 
 void kvmppc_core_commit_memory_region(struct kvm *kvm,
-                               struct kvm_userspace_memory_region *mem)
+                               struct kvm_userspace_memory_region *mem,
+                               struct kvm_memory_slot old)
+{
+}
+
+void kvmppc_core_flush_memslot(struct kvm *kvm, struct kvm_memory_slot *memslot)
 {
 }
 

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 514405752988e6491bebd1962dd322a08147cd36..3a6490fc6fcd30bad695d319c2830d440511296e 100644 (file)
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1457,7 +1457,12 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
 }
 
 void kvmppc_core_commit_memory_region(struct kvm *kvm,
-                               struct kvm_userspace_memory_region *mem)
+                               struct kvm_userspace_memory_region *mem,
+                               struct kvm_memory_slot old)
+{
+}
+
+void kvmppc_core_flush_memslot(struct kvm *kvm, struct kvm_memory_slot *memslot)
 {
 }
 

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 33122dd89da947647e71ddf424ed3574a27b4e13..8443e23f36052e30fde8873a527323b0f14e9f4f 100644 (file)
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -411,7 +411,7 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
                struct kvm_memory_slot old,
                int user_alloc)
 {
-       kvmppc_core_commit_memory_region(kvm, mem);
+       kvmppc_core_commit_memory_region(kvm, mem, old);
 }
 
 void kvm_arch_flush_shadow_all(struct kvm *kvm)
@@ -421,6 +421,7 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm)
 void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
                                   struct kvm_memory_slot *slot)
 {
+       kvmppc_core_flush_memslot(kvm, slot);
 }
 
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)