KVM: x86: MMU: Make mmu_set_spte() return emulate value

mmu_set_spte()'s code is based on the assumption that the emulate
parameter has a valid pointer value if set_spte() returns true and
write_fault is not zero.  In other cases, emulate may be NULL, so a
NULL-check is needed.

Stop passing emulate pointer and make mmu_set_spte() return the emulate
value instead to clean up this complex interface.  Prefetch functions
can just throw away the return value.

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 9832bc9e937e5e1f201c18b26bc6f241c8310796..74c120cd63fd0aa73e7413b47460d63b02df3601 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2564,13 +2564,13 @@ done:
        return ret;
 }
 
-static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
-                        unsigned pte_access, int write_fault, int *emulate,
-                        int level, gfn_t gfn, pfn_t pfn, bool speculative,
-                        bool host_writable)
+static bool mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access,
+                        int write_fault, int level, gfn_t gfn, pfn_t pfn,
+                        bool speculative, bool host_writable)
 {
        int was_rmapped = 0;
        int rmap_count;
+       bool emulate = false;
 
        pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
                 *sptep, write_fault, gfn);
@@ -2600,12 +2600,12 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
        if (set_spte(vcpu, sptep, pte_access, level, gfn, pfn, speculative,
              true, host_writable)) {
                if (write_fault)
-                       *emulate = 1;
+                       emulate = true;
                kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
        }
 
-       if (unlikely(is_mmio_spte(*sptep) && emulate))
-               *emulate = 1;
+       if (unlikely(is_mmio_spte(*sptep)))
+               emulate = true;
 
        pgprintk("%s: setting spte %llx\n", __func__, *sptep);
        pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n",
@@ -2624,6 +2624,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
        }
 
        kvm_release_pfn_clean(pfn);
+
+       return emulate;
 }
 
 static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
@@ -2658,9 +2660,8 @@ static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
                return -1;
 
        for (i = 0; i < ret; i++, gfn++, start++)
-               mmu_set_spte(vcpu, start, access, 0, NULL,
-                            sp->role.level, gfn, page_to_pfn(pages[i]),
-                            true, true);
+               mmu_set_spte(vcpu, start, access, 0, sp->role.level, gfn,
+                            page_to_pfn(pages[i]), true, true);
 
        return 0;
 }
@@ -2721,9 +2722,9 @@ static int __direct_map(struct kvm_vcpu *vcpu, int write, int map_writable,
 
        for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
                if (iterator.level == level) {
-                       mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
-                                    write, &emulate, level, gfn, pfn,
-                                    prefault, map_writable);
+                       emulate = mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
+                                              write, level, gfn, pfn, prefault,
+                                              map_writable);
                        direct_pte_prefetch(vcpu, iterator.sptep);
                        ++vcpu->stat.pf_fixed;
                        break;

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index d8fdc5cd2e5fff44c114d1ab92d536f08b6169f5..11650eac1c6e83c88d451ed5703423841efeee14 100644 (file)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -475,8 +475,8 @@ FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
         * we call mmu_set_spte() with host_writable = true because
         * pte_prefetch_gfn_to_pfn always gets a writable pfn.
         */
-       mmu_set_spte(vcpu, spte, pte_access, 0, NULL, PT_PAGE_TABLE_LEVEL,
-                    gfn, pfn, true, true);
+       mmu_set_spte(vcpu, spte, pte_access, 0, PT_PAGE_TABLE_LEVEL, gfn, pfn,
+                    true, true);
 
        return true;
 }
@@ -556,7 +556,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
        struct kvm_mmu_page *sp = NULL;
        struct kvm_shadow_walk_iterator it;
        unsigned direct_access, access = gw->pt_access;
-       int top_level, emulate = 0;
+       int top_level, emulate;
 
        direct_access = gw->pte_access;
 
@@ -622,8 +622,8 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
        }
 
        clear_sp_write_flooding_count(it.sptep);
-       mmu_set_spte(vcpu, it.sptep, gw->pte_access, write_fault, &emulate,
-                    it.level, gw->gfn, pfn, prefault, map_writable);
+       emulate = mmu_set_spte(vcpu, it.sptep, gw->pte_access, write_fault,
+                              it.level, gw->gfn, pfn, prefault, map_writable);
        FNAME(pte_prefetch)(vcpu, gw, it.sptep);
 
        return emulate;