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KVM: Move setting of memslot into helper routine 

Split out the core functionality of setting a memslot into a separate
helper in preparation for moving memslot deletion into its own routine.

Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2020-02-18 13:07:23 -08:00 committed by Paolo Bonzini
parent 71a4c30bf0
commit cf47f50b5c
1 changed files with 63 additions and 43 deletions
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106
virt/kvm/kvm_main.c
View File

@ -983,6 +983,66 @@ static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
return old_memslots;
}
static int kvm_set_memslot(struct kvm *kvm,
const struct kvm_userspace_memory_region *mem,
const struct kvm_memory_slot *old,
struct kvm_memory_slot *new, int as_id,
enum kvm_mr_change change)
{
struct kvm_memory_slot *slot;
struct kvm_memslots *slots;
int r;
slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
if (!slots)
return -ENOMEM;
memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
/*
* Note, the INVALID flag needs to be in the appropriate entry
* in the freshly allocated memslots, not in @old or @new.
*/
slot = id_to_memslot(slots, old->id);
slot->flags |= KVM_MEMSLOT_INVALID;
/*
* We can re-use the old memslots, the only difference from the
* newly installed memslots is the invalid flag, which will get
* dropped by update_memslots anyway. We'll also revert to the
* old memslots if preparing the new memory region fails.
*/
slots = install_new_memslots(kvm, as_id, slots);
/* From this point no new shadow pages pointing to a deleted,
* or moved, memslot will be created.
*
* validation of sp->gfn happens in:
* - gfn_to_hva (kvm_read_guest, gfn_to_pfn)
* - kvm_is_visible_gfn (mmu_check_root)
*/
kvm_arch_flush_shadow_memslot(kvm, slot);
}
r = kvm_arch_prepare_memory_region(kvm, new, mem, change);
if (r)
goto out_slots;
update_memslots(slots, new, change);
slots = install_new_memslots(kvm, as_id, slots);
kvm_arch_commit_memory_region(kvm, mem, old, new, change);
kvfree(slots);
return 0;
out_slots:
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
slots = install_new_memslots(kvm, as_id, slots);
kvfree(slots);
return r;
}
/*
* Allocate some memory and give it an address in the guest physical address
* space.
@ -999,7 +1059,6 @@ int __kvm_set_memory_region(struct kvm *kvm,
unsigned long npages;
struct kvm_memory_slot *slot;
struct kvm_memory_slot old, new;
struct kvm_memslots *slots;
int as_id, id;
enum kvm_mr_change change;
@ -1086,58 +1145,19 @@ int __kvm_set_memory_region(struct kvm *kvm,
return r;
}
slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
if (!slots) {
r = -ENOMEM;
goto out_bitmap;
}
memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
slot = id_to_memslot(slots, id);
slot->flags |= KVM_MEMSLOT_INVALID;
/*
* We can re-use the old memslots, the only difference from the
* newly installed memslots is the invalid flag, which will get
* dropped by update_memslots anyway. We'll also revert to the
* old memslots if preparing the new memory region fails.
*/
slots = install_new_memslots(kvm, as_id, slots);
/* From this point no new shadow pages pointing to a deleted,
* or moved, memslot will be created.
*
* validation of sp->gfn happens in:
* - gfn_to_hva (kvm_read_guest, gfn_to_pfn)
* - kvm_is_visible_gfn (mmu_check_root)
*/
kvm_arch_flush_shadow_memslot(kvm, slot);
}
r = kvm_arch_prepare_memory_region(kvm, &new, mem, change);
if (r)
goto out_slots;
/* actual memory is freed via old in kvm_free_memslot below */
if (change == KVM_MR_DELETE) {
new.dirty_bitmap = NULL;
memset(&new.arch, 0, sizeof(new.arch));
}
update_memslots(slots, &new, change);
slots = install_new_memslots(kvm, as_id, slots);
kvm_arch_commit_memory_region(kvm, mem, &old, &new, change);
r = kvm_set_memslot(kvm, mem, &old, &new, as_id, change);
if (r)
goto out_bitmap;
kvm_free_memslot(kvm, &old, &new);
kvfree(slots);
return 0;
out_slots:
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
slots = install_new_memslots(kvm, as_id, slots);
kvfree(slots);
out_bitmap:
if (new.dirty_bitmap && !old.dirty_bitmap)
kvm_destroy_dirty_bitmap(&new);