Add infrastructure that handles protected memory extension.
Arch-specific code has to provide hypercalls and define non-zero
VM_KVM_PROTECTED.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
include/linux/kvm_host.h | 4 +++
virt/kvm/Kconfig | 3 ++
virt/kvm/kvm_main.c | 68 ++++++++++++++++++++++++++++++++++++++
virt/lib/Makefile | 1 +
virt/lib/mem_protected.c | 71 ++++++++++++++++++++++++++++++++++++++++
5 files changed, 147 insertions(+)
create mode 100644 virt/lib/mem_protected.c
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 380a64613880..6655e8da4555 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -701,6 +701,10 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm);
void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot);
+int kvm_protect_all_memory(struct kvm *kvm);
+int kvm_protect_memory(struct kvm *kvm,
+ unsigned long gfn, unsigned long npages, bool protect);
+
int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
struct page **pages, int nr_pages);
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 1c37ccd5d402..50d7422386aa 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -63,3 +63,6 @@ config HAVE_KVM_NO_POLL
config KVM_XFER_TO_GUEST_WORK
bool
+
+config HAVE_KVM_PROTECTED_MEMORY
+ bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 125db5a73e10..4c008c7b4974 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -154,6 +154,8 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
static unsigned long long kvm_createvm_count;
static unsigned long long kvm_active_vms;
+int __kvm_protect_memory(unsigned long start, unsigned long end, bool protect);
+
__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
unsigned long start, unsigned long end)
{
@@ -1371,6 +1373,15 @@ int __kvm_set_memory_region(struct kvm *kvm,
if (r)
goto out_bitmap;
+ if (IS_ENABLED(CONFIG_HAVE_KVM_PROTECTED_MEMORY) &&
+ mem->memory_size && kvm->mem_protected) {
+ r = __kvm_protect_memory(new.userspace_addr,
+ new.userspace_addr + new.npages * PAGE_SIZE,
+ true);
+ if (r)
+ goto out_bitmap;
+ }
+
if (old.dirty_bitmap && !new.dirty_bitmap)
kvm_destroy_dirty_bitmap(&old);
return 0;
@@ -2720,6 +2731,63 @@ void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty);
+int kvm_protect_memory(struct kvm *kvm,
+ unsigned long gfn, unsigned long npages, bool protect)
+{
+ struct kvm_memory_slot *memslot;
+ unsigned long start, end;
+ gfn_t numpages;
+
+ if (!IS_ENABLED(CONFIG_HAVE_KVM_PROTECTED_MEMORY))
+ return -KVM_ENOSYS;
+
+ if (!npages)
+ return 0;
+
+ memslot = gfn_to_memslot(kvm, gfn);
+ /* Not backed by memory. It's okay. */
+ if (!memslot)
+ return 0;
+
+ start = gfn_to_hva_many(memslot, gfn, &numpages);
+ end = start + npages * PAGE_SIZE;
+
+ /* XXX: Share range across memory slots? */
+ if (WARN_ON(numpages < npages))
+ return -EINVAL;
+
+ return __kvm_protect_memory(start, end, protect);
+}
+EXPORT_SYMBOL_GPL(kvm_protect_memory);
+
+int kvm_protect_all_memory(struct kvm *kvm)
+{
+ struct kvm_memslots *slots;
+ struct kvm_memory_slot *memslot;
+ unsigned long start, end;
+ int i, ret = 0;;
+
+ if (!IS_ENABLED(CONFIG_HAVE_KVM_PROTECTED_MEMORY))
+ return -KVM_ENOSYS;
+
+ mutex_lock(&kvm->slots_lock);
+ kvm->mem_protected = true;
+ for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ slots = __kvm_memslots(kvm, i);
+ kvm_for_each_memslot(memslot, slots) {
+ start = memslot->userspace_addr;
+ end = start + memslot->npages * PAGE_SIZE;
+ ret = __kvm_protect_memory(start, end, true);
+ if (ret)
+ goto out;
+ }
+ }
+out:
+ mutex_unlock(&kvm->slots_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_protect_all_memory);
+
void kvm_sigset_activate(struct kvm_vcpu *vcpu)
{
if (!vcpu->sigset_active)
diff --git a/virt/lib/Makefile b/virt/lib/Makefile
index bd7f9a78bb6b..d6e50510801f 100644
--- a/virt/lib/Makefile
+++ b/virt/lib/Makefile
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_IRQ_BYPASS_MANAGER) += irqbypass.o
+obj-$(CONFIG_HAVE_KVM_PROTECTED_MEMORY) += mem_protected.o
diff --git a/virt/lib/mem_protected.c b/virt/lib/mem_protected.c
new file mode 100644
index 000000000000..0b01dd74f29c
--- /dev/null
+++ b/virt/lib/mem_protected.c
@@ -0,0 +1,71 @@
+#include <linux/kvm_host.h>
+#include <linux/mm.h>
+#include <linux/pagewalk.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <asm/tlbflush.h>
+
+int __kvm_protect_memory(unsigned long start, unsigned long end, bool protect)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma, *prev;
+ int ret;
+
+ if (mmap_write_lock_killable(mm))
+ return -EINTR;
+
+ ret = -ENOMEM;
+ vma = find_vma(current->mm, start);
+ if (!vma)
+ goto out;
+
+ ret = -EINVAL;
+ if (vma->vm_start > start)
+ goto out;
+
+ if (start > vma->vm_start)
+ prev = vma;
+ else
+ prev = vma->vm_prev;
+
+ ret = 0;
+ while (true) {
+ unsigned long newflags, tmp;
+
+ tmp = vma->vm_end;
+ if (tmp > end)
+ tmp = end;
+
+ newflags = vma->vm_flags;
+ if (protect)
+ newflags |= VM_KVM_PROTECTED;
+ else
+ newflags &= ~VM_KVM_PROTECTED;
+
+ /* The VMA has been handled as part of other memslot */
+ if (newflags == vma->vm_flags)
+ goto next;
+
+ ret = mprotect_fixup(vma, &prev, start, tmp, newflags);
+ if (ret)
+ goto out;
+
+next:
+ start = tmp;
+ if (start < prev->vm_end)
+ start = prev->vm_end;
+
+ if (start >= end)
+ goto out;
+
+ vma = prev->vm_next;
+ if (!vma || vma->vm_start != start) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+out:
+ mmap_write_unlock(mm);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__kvm_protect_memory);
--
2.26.2
