On Wed, Jun 10, 2020 at 03:00:47PM -0700, Ben Gardon wrote:

On Fri, Jun 5, 2020 at 2:39 PM Sean Christopherson
[off-list ref] wrote:

quoted

Replace the @max param in mmu_topup_memory_cache() and instead use
ARRAY_SIZE() to terminate the loop to fill the cache.  This removes a
BUG_ON() and sets the stage for moving arm64 to the common memory cache
implementation.

No functional change intended.

Signed-off-by: Sean Christopherson <redacted>
---
 arch/arm64/kvm/mmu.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index a1f6bc70c4e4..9398b66f8a87 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c

@@ -124,15 +124,13 @@ static void stage2_dissolve_pud(struct kvm *kvm, phys_addr_t addr, pud_t *pudp)
        put_page(virt_to_page(pudp));
 }

-static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
-                                 int min, int max)
+static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, int min)
 {
        void *page;

-       BUG_ON(max > KVM_NR_MEM_OBJS);

KVM_NR_MEM_OBJS should be undefined as of patch 14 in this series. I'd
recommend changing this to use the new constant you defined in that
patch.

My intent was to leave KVM_NR_MEM_OBJS defined by arm64 and MIPS until they
move to the common implementation, e.g. this should be defined in
arch/arm64/include/asm/kvm_host.h until patch 18.  I'll get cross-compiling
setup so I can properly test bisection before sending v2.

quoted

        if (cache->nobjs >= min)
                return 0;
-       while (cache->nobjs < max) {
+       while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
                page = (void *)__get_free_page(GFP_PGTABLE_USER);
                if (!page)
                        return -ENOMEM;

@@ -1356,8 +1354,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
                        pte = kvm_s2pte_mkwrite(pte);

                ret = mmu_topup_memory_cache(&cache,
-                                            kvm_mmu_cache_min_pages(kvm),
-                                            KVM_NR_MEM_OBJS);

See above, KVM_NR_MEM_OBJS is undefined as of patch 14.

quoted

+                                            kvm_mmu_cache_min_pages(kvm));
                if (ret)
                        goto out;
                spin_lock(&kvm->mmu_lock);

@@ -1737,8 +1734,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
        up_read(&current->mm->mmap_sem);

        /* We need minimum second+third level pages */
-       ret = mmu_topup_memory_cache(memcache, kvm_mmu_cache_min_pages(kvm),
-                                    KVM_NR_MEM_OBJS);

See above, KVM_NR_MEM_OBJS is undefined as of patch 14.

quoted

+       ret = mmu_topup_memory_cache(memcache, kvm_mmu_cache_min_pages(kvm));
        if (ret)
                return ret;

--
2.26.0

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