On Fri, Aug 19, 2022 at 12:37:42PM -0700, Vishal Annapurve wrote:
... diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 230c8ff9659c..bb714c2a4b06 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -914,6 +914,35 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
+#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM +#define KVM_MEM_ATTR_PRIVATE 0x0001 +static int kvm_vm_ioctl_set_encrypted_region(struct kvm *kvm, unsigned int ioctl,
struct kvm_enc_region *region)+{
unsigned long start, end;void *entry;int r;if (region->size == 0 || region->addr + region->size < region->addr)return -EINVAL;if (region->addr & (PAGE_SIZE - 1) || region->size & (PAGE_SIZE - 1))return -EINVAL;start = region->addr >> PAGE_SHIFT;end = (region->addr + region->size - 1) >> PAGE_SHIFT;entry = ioctl == KVM_MEMORY_ENCRYPT_REG_REGION ?xa_mk_value(KVM_MEM_ATTR_PRIVATE) : NULL;r = xa_err(xa_store_range(&kvm->mem_attr_array, start, end,entry, GFP_KERNEL_ACCOUNT));xa_store_range seems to create multi-index entries by default. Subsequent xa_store_range call changes all the entries stored previously.
By using xa_store_range and storing them as multi-index entries I expected to save some memory for continuous pages originally.
But sounds like the current multi-index store behaviour isn't quite ready for our usage.
Chao
xa_store needs to be used here instead of xa_store_range to achieve the intended behavior.
kvm_zap_gfn_range(kvm, start, end + 1);return r;+} +#endif /* CONFIG_HAVE_KVM_PRIVATE_MEM */
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