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* fix latent bug in how usage of large pages is determined for

Browse Source 
confidential VMs
 
 * fix "underline too short" in docs
 
 * eliminate log spam from limited APIC timer periods
 
 * disallow pre-faulting of memory before SEV-SNP VMs are initialized
 
 * delay clearing and encrypting private memory until it is added to
   guest page tables
 
 * this change also enables another small cleanup: the checks in
   SNP_LAUNCH_UPDATE that limit it to non-populated, private pages
   can now be moved in the common kvm_gmem_populate() function
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Merge branch 'kvm-fixes' into HEAD

* fix latent bug in how usage of large pages is determined for
  confidential VMs

* fix "underline too short" in docs

* eliminate log spam from limited APIC timer periods

* disallow pre-faulting of memory before SEV-SNP VMs are initialized

* delay clearing and encrypting private memory until it is added to
  guest page tables

* this change also enables another small cleanup: the checks in
  SNP_LAUNCH_UPDATE that limit it to non-populated, private pages
  can now be moved in the common kvm_gmem_populate() function
This commit is contained in:
Paolo Bonzini 2024-08-02 12:31:48 -04:00
commit 1773014a97
12 changed files with 210 additions and 155 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/virt/kvm/api.rst
View File

@ -6368,7 +6368,7 @@ a single guest_memfd file, but the bound ranges must not overlap).
See KVM_SET_USER_MEMORY_REGION2 for additional details.
4.143 KVM_PRE_FAULT_MEMORY
------------------------
---------------------------
:Capability: KVM_CAP_PRE_FAULT_MEMORY
:Architectures: none
@ -6405,6 +6405,12 @@ for the current vCPU state. KVM maps memory as if the vCPU generated a
stage-2 read page fault, e.g. faults in memory as needed, but doesn't break
CoW. However, KVM does not mark any newly created stage-2 PTE as Accessed.
In the case of confidential VM types where there is an initial set up of
private guest memory before the guest is 'finalized'/measured, this ioctl
should only be issued after completing all the necessary setup to put the
guest into a 'finalized' state so that the above semantics can be reliably
ensured.
In some cases, multiple vCPUs might share the page tables. In this
case, the ioctl can be called in parallel.

1
arch/x86/include/asm/kvm_host.h
View File

@ -1305,6 +1305,7 @@ struct kvm_arch {
u8 vm_type;
bool has_private_mem;
bool has_protected_state;
bool pre_fault_allowed;
struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];
struct list_head active_mmu_pages;
struct list_head zapped_obsolete_pages;

4
arch/x86/kvm/Kconfig
View File

@ -141,8 +141,8 @@ config KVM_AMD_SEV
depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
select ARCH_HAS_CC_PLATFORM
select KVM_GENERIC_PRIVATE_MEM
select HAVE_KVM_GMEM_PREPARE
select HAVE_KVM_GMEM_INVALIDATE
select HAVE_KVM_ARCH_GMEM_PREPARE
select HAVE_KVM_ARCH_GMEM_INVALIDATE
help
Provides support for launching Encrypted VMs (SEV) and Encrypted VMs
with Encrypted State (SEV-ES) on AMD processors.

2
arch/x86/kvm/lapic.c
View File

@ -1743,7 +1743,7 @@ static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
s64 min_period = min_timer_period_us * 1000LL;
if (apic->lapic_timer.period < min_period) {
pr_info_ratelimited(
pr_info_once(
"vcpu %i: requested %lld ns "
"lapic timer period limited to %lld ns\n",
apic->vcpu->vcpu_id,

7
arch/x86/kvm/mmu/mmu.c
View File

@ -4335,7 +4335,7 @@ static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn,
if (req_max_level)
max_level = min(max_level, req_max_level);
return req_max_level;
return max_level;
}
static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu,
@ -4743,6 +4743,9 @@ long kvm_arch_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu,
u64 end;
int r;
if (!vcpu->kvm->arch.pre_fault_allowed)
return -EOPNOTSUPP;
/*
* reload is efficient when called repeatedly, so we can do it on
* every iteration.
@ -7510,7 +7513,7 @@ static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot,
const unsigned long end = start + KVM_PAGES_PER_HPAGE(level);
if (level == PG_LEVEL_2M)
return kvm_range_has_memory_attributes(kvm, start, end, attrs);
return kvm_range_has_memory_attributes(kvm, start, end, ~0, attrs);
for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) {
if (hugepage_test_mixed(slot, gfn, level - 1) ||

17
arch/x86/kvm/svm/sev.c
View File

@ -2279,18 +2279,11 @@ static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn_start, kvm_pfn_t pf
bool assigned;
int level;
if (!kvm_mem_is_private(kvm, gfn)) {
pr_debug("%s: Failed to ensure GFN 0x%llx has private memory attribute set\n",
__func__, gfn);
ret = -EINVAL;
goto err;
}
ret = snp_lookup_rmpentry((u64)pfn + i, &assigned, &level);
if (ret || assigned) {
pr_debug("%s: Failed to ensure GFN 0x%llx RMP entry is initial shared state, ret: %d assigned: %d\n",
__func__, gfn, ret, assigned);
ret = -EINVAL;
ret = ret ? -EINVAL : -EEXIST;
goto err;
}
@ -2549,6 +2542,14 @@ static int snp_launch_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
data->gctx_paddr = __psp_pa(sev->snp_context);
ret = sev_issue_cmd(kvm, SEV_CMD_SNP_LAUNCH_FINISH, data, &argp->error);
/*
* Now that there will be no more SNP_LAUNCH_UPDATE ioctls, private pages
* can be given to the guest simply by marking the RMP entry as private.
* This can happen on first access and also with KVM_PRE_FAULT_MEMORY.
*/
if (!ret)
kvm->arch.pre_fault_allowed = true;
kfree(id_auth);
e_free_id_block:

1
arch/x86/kvm/svm/svm.c
View File

@ -4949,6 +4949,7 @@ static int svm_vm_init(struct kvm *kvm)
to_kvm_sev_info(kvm)->need_init = true;
kvm->arch.has_private_mem = (type == KVM_X86_SNP_VM);
kvm->arch.pre_fault_allowed = !kvm->arch.has_private_mem;
}
if (!pause_filter_count || !pause_filter_thresh)

12
arch/x86/kvm/x86.c
View File

@ -12646,6 +12646,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm->arch.vm_type = type;
kvm->arch.has_private_mem =
(type == KVM_X86_SW_PROTECTED_VM);
/* Decided by the vendor code for other VM types. */
kvm->arch.pre_fault_allowed =
type == KVM_X86_DEFAULT_VM || type == KVM_X86_SW_PROTECTED_VM;
ret = kvm_page_track_init(kvm);
if (ret)
@ -13641,19 +13644,14 @@ bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_arch_no_poll);
#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
bool kvm_arch_gmem_prepare_needed(struct kvm *kvm)
{
return kvm->arch.vm_type == KVM_X86_SNP_VM;
}
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE
int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order)
{
return kvm_x86_call(gmem_prepare)(kvm, pfn, gfn, max_order);
}
#endif
#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end)
{
kvm_x86_call(gmem_invalidate)(start, end);

9
include/linux/kvm_host.h
View File

@ -2414,7 +2414,7 @@ static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn
}
bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
unsigned long attrs);
unsigned long mask, unsigned long attrs);
bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
struct kvm_gfn_range *range);
bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
@ -2445,11 +2445,11 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm,
}
#endif /* CONFIG_KVM_PRIVATE_MEM */
#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE
int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order);
bool kvm_arch_gmem_prepare_needed(struct kvm *kvm);
#endif
#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM
/**
* kvm_gmem_populate() - Populate/prepare a GPA range with guest data
*
@ -2476,8 +2476,9 @@ typedef int (*kvm_gmem_populate_cb)(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
long kvm_gmem_populate(struct kvm *kvm, gfn_t gfn, void __user *src, long npages,
kvm_gmem_populate_cb post_populate, void *opaque);
#endif
#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);
#endif

4
virt/kvm/Kconfig
View File

@ -113,10 +113,10 @@ config KVM_GENERIC_PRIVATE_MEM
select KVM_PRIVATE_MEM
bool
config HAVE_KVM_GMEM_PREPARE
config HAVE_KVM_ARCH_GMEM_PREPARE
bool
depends on KVM_PRIVATE_MEM
config HAVE_KVM_GMEM_INVALIDATE
config HAVE_KVM_ARCH_GMEM_INVALIDATE
bool
depends on KVM_PRIVATE_MEM

227
virt/kvm/guest_memfd.c
View File

@ -13,84 +13,93 @@ struct kvm_gmem {
struct list_head entry;
};
static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct folio *folio)
/**
* folio_file_pfn - like folio_file_page, but return a pfn.
* @folio: The folio which contains this index.
* @index: The index we want to look up.
*
* Return: The pfn for this index.
*/
static inline kvm_pfn_t folio_file_pfn(struct folio *folio, pgoff_t index)
{
#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
struct list_head *gmem_list = &inode->i_mapping->i_private_list;
struct kvm_gmem *gmem;
return folio_pfn(folio) + (index & (folio_nr_pages(folio) - 1));
}
list_for_each_entry(gmem, gmem_list, entry) {
struct kvm_memory_slot *slot;
struct kvm *kvm = gmem->kvm;
struct page *page;
kvm_pfn_t pfn;
gfn_t gfn;
int rc;
if (!kvm_arch_gmem_prepare_needed(kvm))
continue;
slot = xa_load(&gmem->bindings, index);
if (!slot)
continue;
page = folio_file_page(folio, index);
pfn = page_to_pfn(page);
gfn = slot->base_gfn + index - slot->gmem.pgoff;
rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, compound_order(compound_head(page)));
if (rc) {
pr_warn_ratelimited("gmem: Failed to prepare folio for index %lx GFN %llx PFN %llx error %d.\n",
index, gfn, pfn, rc);
return rc;
}
static int __kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot,
pgoff_t index, struct folio *folio)
{
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE
kvm_pfn_t pfn = folio_file_pfn(folio, index);
gfn_t gfn = slot->base_gfn + index - slot->gmem.pgoff;
int rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, folio_order(folio));
if (rc) {
pr_warn_ratelimited("gmem: Failed to prepare folio for index %lx GFN %llx PFN %llx error %d.\n",
index, gfn, pfn, rc);
return rc;
}
#endif
return 0;
}
static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index, bool prepare)
static inline void kvm_gmem_mark_prepared(struct folio *folio)
{
struct folio *folio;
folio_mark_uptodate(folio);
}
/* TODO: Support huge pages. */
folio = filemap_grab_folio(inode->i_mapping, index);
if (IS_ERR(folio))
return folio;
/*
* Process @folio, which contains @gfn, so that the guest can use it.
* The folio must be locked and the gfn must be contained in @slot.
* On successful return the guest sees a zero page so as to avoid
* leaking host data and the up-to-date flag is set.
*/
static int kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot,
gfn_t gfn, struct folio *folio)
{
unsigned long nr_pages, i;
pgoff_t index;
int r;
nr_pages = folio_nr_pages(folio);
for (i = 0; i < nr_pages; i++)
clear_highpage(folio_page(folio, i));
/*
* Use the up-to-date flag to track whether or not the memory has been
* zeroed before being handed off to the guest. There is no backing
* storage for the memory, so the folio will remain up-to-date until
* it's removed.
* Preparing huge folios should always be safe, since it should
* be possible to split them later if needed.
*
* TODO: Skip clearing pages when trusted firmware will do it when
* assigning memory to the guest.
* Right now the folio order is always going to be zero, but the
* code is ready for huge folios. The only assumption is that
* the base pgoff of memslots is naturally aligned with the
* requested page order, ensuring that huge folios can also use
* huge page table entries for GPA->HPA mapping.
*
* The order will be passed when creating the guest_memfd, and
* checked when creating memslots.
*/
if (!folio_test_uptodate(folio)) {
unsigned long nr_pages = folio_nr_pages(folio);
unsigned long i;
WARN_ON(!IS_ALIGNED(slot->gmem.pgoff, 1 << folio_order(folio)));
index = gfn - slot->base_gfn + slot->gmem.pgoff;
index = ALIGN_DOWN(index, 1 << folio_order(folio));
r = __kvm_gmem_prepare_folio(kvm, slot, index, folio);
if (!r)
kvm_gmem_mark_prepared(folio);
for (i = 0; i < nr_pages; i++)
clear_highpage(folio_page(folio, i));
return r;
}
folio_mark_uptodate(folio);
}
if (prepare) {
int r = kvm_gmem_prepare_folio(inode, index, folio);
if (r < 0) {
folio_unlock(folio);
folio_put(folio);
return ERR_PTR(r);
}
}
/*
* Ignore accessed, referenced, and dirty flags. The memory is
* unevictable and there is no storage to write back to.
*/
return folio;
/*
* Returns a locked folio on success. The caller is responsible for
* setting the up-to-date flag before the memory is mapped into the guest.
* There is no backing storage for the memory, so the folio will remain
* up-to-date until it's removed.
*
* Ignore accessed, referenced, and dirty flags. The memory is
* unevictable and there is no storage to write back to.
*/
static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index)
{
/* TODO: Support huge pages. */
return filemap_grab_folio(inode->i_mapping, index);
}
static void kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start,
@ -190,7 +199,7 @@ static long kvm_gmem_allocate(struct inode *inode, loff_t offset, loff_t len)
break;
}
folio = kvm_gmem_get_folio(inode, index, true);
folio = kvm_gmem_get_folio(inode, index);
if (IS_ERR(folio)) {
r = PTR_ERR(folio);
break;
@ -343,7 +352,7 @@ static int kvm_gmem_error_folio(struct address_space *mapping, struct folio *fol
return MF_DELAYED;
}
#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
static void kvm_gmem_free_folio(struct folio *folio)
{
struct page *page = folio_page(folio, 0);
@ -358,7 +367,7 @@ static const struct address_space_operations kvm_gmem_aops = {
.dirty_folio = noop_dirty_folio,
.migrate_folio = kvm_gmem_migrate_folio,
.error_remove_folio = kvm_gmem_error_folio,
#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
.free_folio = kvm_gmem_free_folio,
#endif
};
@ -541,64 +550,76 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot)
fput(file);
}
static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot,
gfn_t gfn, kvm_pfn_t *pfn, int *max_order, bool prepare)
/* Returns a locked folio on success. */
static struct folio *
__kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot,
gfn_t gfn, kvm_pfn_t *pfn, bool *is_prepared,
int *max_order)
{
pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff;
struct kvm_gmem *gmem = file->private_data;
struct folio *folio;
struct page *page;
int r;
if (file != slot->gmem.file) {
WARN_ON_ONCE(slot->gmem.file);
return -EFAULT;
return ERR_PTR(-EFAULT);
}
gmem = file->private_data;
if (xa_load(&gmem->bindings, index) != slot) {
WARN_ON_ONCE(xa_load(&gmem->bindings, index));
return -EIO;
return ERR_PTR(-EIO);
}
folio = kvm_gmem_get_folio(file_inode(file), index, prepare);
folio = kvm_gmem_get_folio(file_inode(file), index);
if (IS_ERR(folio))
return PTR_ERR(folio);
return folio;
if (folio_test_hwpoison(folio)) {
folio_unlock(folio);
folio_put(folio);
return -EHWPOISON;
return ERR_PTR(-EHWPOISON);
}
page = folio_file_page(folio, index);
*pfn = page_to_pfn(page);
*pfn = folio_file_pfn(folio, index);
if (max_order)
*max_order = 0;
r = 0;
folio_unlock(folio);
return r;
*is_prepared = folio_test_uptodate(folio);
return folio;
}
int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
gfn_t gfn, kvm_pfn_t *pfn, int *max_order)
{
struct file *file = kvm_gmem_get_file(slot);
int r;
struct folio *folio;
bool is_prepared = false;
int r = 0;
if (!file)
return -EFAULT;
r = __kvm_gmem_get_pfn(file, slot, gfn, pfn, max_order, true);
folio = __kvm_gmem_get_pfn(file, slot, gfn, pfn, &is_prepared, max_order);
if (IS_ERR(folio)) {
r = PTR_ERR(folio);
goto out;
}
if (!is_prepared)
r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio);
folio_unlock(folio);
if (r < 0)
folio_put(folio);
out:
fput(file);
return r;
}
EXPORT_SYMBOL_GPL(kvm_gmem_get_pfn);
#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM
long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long npages,
kvm_gmem_populate_cb post_populate, void *opaque)
{
@ -625,7 +646,9 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long
npages = min_t(ulong, slot->npages - (start_gfn - slot->base_gfn), npages);
for (i = 0; i < npages; i += (1 << max_order)) {
struct folio *folio;
gfn_t gfn = start_gfn + i;
bool is_prepared = false;
kvm_pfn_t pfn;
if (signal_pending(current)) {
@ -633,18 +656,39 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long
break;
}
ret = __kvm_gmem_get_pfn(file, slot, gfn, &pfn, &max_order, false);
if (ret)
folio = __kvm_gmem_get_pfn(file, slot, gfn, &pfn, &is_prepared, &max_order);
if (IS_ERR(folio)) {
ret = PTR_ERR(folio);
break;
}
if (!IS_ALIGNED(gfn, (1 << max_order)) ||
(npages - i) < (1 << max_order))
max_order = 0;
if (is_prepared) {
folio_unlock(folio);
folio_put(folio);
ret = -EEXIST;
break;
}
folio_unlock(folio);
WARN_ON(!IS_ALIGNED(gfn, 1 << max_order) ||
(npages - i) < (1 << max_order));
ret = -EINVAL;
while (!kvm_range_has_memory_attributes(kvm, gfn, gfn + (1 << max_order),
KVM_MEMORY_ATTRIBUTE_PRIVATE,
KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
if (!max_order)
goto put_folio_and_exit;
max_order--;
}
p = src ? src + i * PAGE_SIZE : NULL;
ret = post_populate(kvm, gfn, pfn, p, max_order, opaque);
if (!ret)
kvm_gmem_mark_prepared(folio);
put_page(pfn_to_page(pfn));
put_folio_and_exit:
folio_put(folio);
if (ret)
break;
}
@ -655,3 +699,4 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long
return ret && !i ? ret : i;
}
EXPORT_SYMBOL_GPL(kvm_gmem_populate);
#endif

73
virt/kvm/kvm_main.c
View File

@ -2398,42 +2398,6 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
#endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
/*
* Returns true if _all_ gfns in the range [@start, @end) have attributes
* matching @attrs.
*/
bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
unsigned long attrs)
{
XA_STATE(xas, &kvm->mem_attr_array, start);
unsigned long index;
bool has_attrs;
void *entry;
rcu_read_lock();
if (!attrs) {
has_attrs = !xas_find(&xas, end - 1);
goto out;
}
has_attrs = true;
for (index = start; index < end; index++) {
do {
entry = xas_next(&xas);
} while (xas_retry(&xas, entry));
if (xas.xa_index != index || xa_to_value(entry) != attrs) {
has_attrs = false;
break;
}
}
out:
rcu_read_unlock();
return has_attrs;
}
static u64 kvm_supported_mem_attributes(struct kvm *kvm)
{
if (!kvm || kvm_arch_has_private_mem(kvm))
@ -2442,6 +2406,41 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm)
return 0;
}
/*
* Returns true if _all_ gfns in the range [@start, @end) have attributes
* such that the bits in @mask match @attrs.
*/
bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
unsigned long mask, unsigned long attrs)
{
XA_STATE(xas, &kvm->mem_attr_array, start);
unsigned long index;
void *entry;
mask &= kvm_supported_mem_attributes(kvm);
if (attrs & ~mask)
return false;
if (end == start + 1)
return (kvm_get_memory_attributes(kvm, start) & mask) == attrs;
guard(rcu)();
if (!attrs)
return !xas_find(&xas, end - 1);
for (index = start; index < end; index++) {
do {
entry = xas_next(&xas);
} while (xas_retry(&xas, entry));
if (xas.xa_index != index ||
(xa_to_value(entry) & mask) != attrs)
return false;
}
return true;
}
static __always_inline void kvm_handle_gfn_range(struct kvm *kvm,
struct kvm_mmu_notifier_range *range)
{
@ -2534,7 +2533,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
mutex_lock(&kvm->slots_lock);
/* Nothing to do if the entire range as the desired attributes. */
if (kvm_range_has_memory_attributes(kvm, start, end, attributes))
if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes))
goto out_unlock;
/*