linux-stable/arch/x86/kvm/mmu/page_track.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Support KVM gust page tracking
*
* This feature allows us to track page access in guest. Currently, only
* write access is tracked.
*
* Copyright(C) 2015 Intel Corporation.
*
* Author:
* Xiao Guangrong <guangrong.xiao@linux.intel.com>
*/
#include <linux/kvm_host.h>
#include <linux/rculist.h>
#include <asm/kvm_page_track.h>
#include "mmu.h"
#include "mmu_internal.h"
bool kvm_page_track_write_tracking_enabled(struct kvm *kvm)
{
return IS_ENABLED(CONFIG_KVM_EXTERNAL_WRITE_TRACKING) ||
!tdp_enabled || kvm_shadow_root_allocated(kvm);
}
void kvm_page_track_free_memslot(struct kvm_memory_slot *slot)
{
int i;
for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
kvfree(slot->arch.gfn_track[i]);
slot->arch.gfn_track[i] = NULL;
}
}
int kvm_page_track_create_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot,
unsigned long npages)
{
int i;
for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
if (i == KVM_PAGE_TRACK_WRITE &&
!kvm_page_track_write_tracking_enabled(kvm))
continue;
treewide: kvzalloc() -> kvcalloc() The kvzalloc() function has a 2-factor argument form, kvcalloc(). This patch replaces cases of: kvzalloc(a * b, gfp) with: kvcalloc(a * b, gfp) as well as handling cases of: kvzalloc(a * b * c, gfp) with: kvzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kvcalloc(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kvzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kvzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kvzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kvzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kvzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kvzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kvzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kvzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kvzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kvzalloc( - sizeof(char) * COUNT + COUNT , ...) | kvzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kvzalloc + kvcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kvzalloc + kvcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kvzalloc + kvcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kvzalloc + kvcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kvzalloc + kvcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kvzalloc + kvcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kvzalloc + kvcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kvzalloc + kvcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kvzalloc + kvcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kvzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kvzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kvzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kvzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kvzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kvzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kvzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kvzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kvzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kvzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kvzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kvzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kvzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kvzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kvzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kvzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kvzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kvzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kvzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kvzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kvzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kvzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kvzalloc(C1 * C2 * C3, ...) | kvzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kvzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kvzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kvzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kvzalloc(sizeof(THING) * C2, ...) | kvzalloc(sizeof(TYPE) * C2, ...) | kvzalloc(C1 * C2 * C3, ...) | kvzalloc(C1 * C2, ...) | - kvzalloc + kvcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kvzalloc + kvcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kvzalloc + kvcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kvzalloc + kvcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kvzalloc + kvcalloc ( - (E1) * E2 + E1, E2 , ...) | - kvzalloc + kvcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kvzalloc + kvcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-12 21:04:48 +00:00
slot->arch.gfn_track[i] =
kvcalloc(npages, sizeof(*slot->arch.gfn_track[i]),
GFP_KERNEL_ACCOUNT);
if (!slot->arch.gfn_track[i])
goto track_free;
}
return 0;
track_free:
kvm_page_track_free_memslot(slot);
return -ENOMEM;
}
static inline bool page_track_mode_is_valid(enum kvm_page_track_mode mode)
{
if (mode < 0 || mode >= KVM_PAGE_TRACK_MAX)
return false;
return true;
}
int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot)
{
unsigned short *gfn_track;
if (slot->arch.gfn_track[KVM_PAGE_TRACK_WRITE])
return 0;
gfn_track = kvcalloc(slot->npages, sizeof(*gfn_track), GFP_KERNEL_ACCOUNT);
if (gfn_track == NULL)
return -ENOMEM;
slot->arch.gfn_track[KVM_PAGE_TRACK_WRITE] = gfn_track;
return 0;
}
static void update_gfn_track(struct kvm_memory_slot *slot, gfn_t gfn,
enum kvm_page_track_mode mode, short count)
{
int index, val;
index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
val = slot->arch.gfn_track[mode][index];
if (WARN_ON(val + count < 0 || val + count > USHRT_MAX))
return;
slot->arch.gfn_track[mode][index] += count;
}
/*
* add guest page to the tracking pool so that corresponding access on that
* page will be intercepted.
*
* It should be called under the protection both of mmu-lock and kvm->srcu
* or kvm->slots_lock.
*
* @kvm: the guest instance we are interested in.
* @slot: the @gfn belongs to.
* @gfn: the guest page.
* @mode: tracking mode, currently only write track is supported.
*/
void kvm_slot_page_track_add_page(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn,
enum kvm_page_track_mode mode)
{
if (WARN_ON(!page_track_mode_is_valid(mode)))
return;
if (WARN_ON(mode == KVM_PAGE_TRACK_WRITE &&
!kvm_page_track_write_tracking_enabled(kvm)))
return;
update_gfn_track(slot, gfn, mode, 1);
/*
* new track stops large page mapping for the
* tracked page.
*/
kvm_mmu_gfn_disallow_lpage(slot, gfn);
if (mode == KVM_PAGE_TRACK_WRITE)
if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
kvm_flush_remote_tlbs(kvm);
}
EXPORT_SYMBOL_GPL(kvm_slot_page_track_add_page);
/*
* remove the guest page from the tracking pool which stops the interception
* of corresponding access on that page. It is the opposed operation of
* kvm_slot_page_track_add_page().
*
* It should be called under the protection both of mmu-lock and kvm->srcu
* or kvm->slots_lock.
*
* @kvm: the guest instance we are interested in.
* @slot: the @gfn belongs to.
* @gfn: the guest page.
* @mode: tracking mode, currently only write track is supported.
*/
void kvm_slot_page_track_remove_page(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn,
enum kvm_page_track_mode mode)
{
if (WARN_ON(!page_track_mode_is_valid(mode)))
return;
if (WARN_ON(mode == KVM_PAGE_TRACK_WRITE &&
!kvm_page_track_write_tracking_enabled(kvm)))
return;
update_gfn_track(slot, gfn, mode, -1);
/*
* allow large page mapping for the tracked page
* after the tracker is gone.
*/
kvm_mmu_gfn_allow_lpage(slot, gfn);
}
EXPORT_SYMBOL_GPL(kvm_slot_page_track_remove_page);
/*
* check if the corresponding access on the specified guest page is tracked.
*/
bool kvm_slot_page_track_is_active(struct kvm *kvm,
const struct kvm_memory_slot *slot,
gfn_t gfn, enum kvm_page_track_mode mode)
{
int index;
if (WARN_ON(!page_track_mode_is_valid(mode)))
return false;
if (!slot)
return false;
if (mode == KVM_PAGE_TRACK_WRITE &&
!kvm_page_track_write_tracking_enabled(kvm))
return false;
index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-23 21:07:29 +00:00
return !!READ_ONCE(slot->arch.gfn_track[mode][index]);
}
void kvm_page_track_cleanup(struct kvm *kvm)
{
struct kvm_page_track_notifier_head *head;
head = &kvm->arch.track_notifier_head;
cleanup_srcu_struct(&head->track_srcu);
}
int kvm_page_track_init(struct kvm *kvm)
{
struct kvm_page_track_notifier_head *head;
head = &kvm->arch.track_notifier_head;
INIT_HLIST_HEAD(&head->track_notifier_list);
return init_srcu_struct(&head->track_srcu);
}
/*
* register the notifier so that event interception for the tracked guest
* pages can be received.
*/
void
kvm_page_track_register_notifier(struct kvm *kvm,
struct kvm_page_track_notifier_node *n)
{
struct kvm_page_track_notifier_head *head;
head = &kvm->arch.track_notifier_head;
write_lock(&kvm->mmu_lock);
hlist_add_head_rcu(&n->node, &head->track_notifier_list);
write_unlock(&kvm->mmu_lock);
}
EXPORT_SYMBOL_GPL(kvm_page_track_register_notifier);
/*
* stop receiving the event interception. It is the opposed operation of
* kvm_page_track_register_notifier().
*/
void
kvm_page_track_unregister_notifier(struct kvm *kvm,
struct kvm_page_track_notifier_node *n)
{
struct kvm_page_track_notifier_head *head;
head = &kvm->arch.track_notifier_head;
write_lock(&kvm->mmu_lock);
hlist_del_rcu(&n->node);
write_unlock(&kvm->mmu_lock);
synchronize_srcu(&head->track_srcu);
}
EXPORT_SYMBOL_GPL(kvm_page_track_unregister_notifier);
/*
* Notify the node that write access is intercepted and write emulation is
* finished at this time.
*
* The node should figure out if the written page is the one that node is
* interested in by itself.
*/
void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
int bytes)
{
struct kvm_page_track_notifier_head *head;
struct kvm_page_track_notifier_node *n;
int idx;
head = &vcpu->kvm->arch.track_notifier_head;
if (hlist_empty(&head->track_notifier_list))
return;
idx = srcu_read_lock(&head->track_srcu);
hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
srcu_read_lock_held(&head->track_srcu))
if (n->track_write)
n->track_write(vcpu, gpa, new, bytes, n);
srcu_read_unlock(&head->track_srcu, idx);
}
/*
* Notify the node that memory slot is being removed or moved so that it can
* drop write-protection for the pages in the memory slot.
*
* The node should figure out it has any write-protected pages in this slot
* by itself.
*/
void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
{
struct kvm_page_track_notifier_head *head;
struct kvm_page_track_notifier_node *n;
int idx;
head = &kvm->arch.track_notifier_head;
if (hlist_empty(&head->track_notifier_list))
return;
idx = srcu_read_lock(&head->track_srcu);
hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
srcu_read_lock_held(&head->track_srcu))
if (n->track_flush_slot)
n->track_flush_slot(kvm, slot, n);
srcu_read_unlock(&head->track_srcu, idx);
}