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Message-ID: <20221206173601.549281-2-bgardon@google.com>
Date: Tue, 6 Dec 2022 17:35:55 +0000
From: Ben Gardon <bgardon@...gle.com>
To: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc: Paolo Bonzini <pbonzini@...hat.com>, Peter Xu <peterx@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
David Matlack <dmatlack@...gle.com>,
Vipin Sharma <vipinsh@...gle.com>,
Ben Gardon <bgardon@...gle.com>
Subject: [PATCH 1/7] KVM: x86/MMU: Move pte_list operations to rmap.c
In the interest of eventually splitting the Shadow MMU out of mmu.c,
start by moving some of the operations for manipulating pte_lists out of
mmu.c and into a new pair of files: rmap.c and rmap.h.
No functional change intended.
Signed-off-by: Ben Gardon <bgardon@...gle.com>
---
arch/x86/kvm/Makefile | 2 +-
arch/x86/kvm/debugfs.c | 1 +
arch/x86/kvm/mmu/mmu.c | 152 +-------------------------------
arch/x86/kvm/mmu/mmu_internal.h | 1 -
arch/x86/kvm/mmu/rmap.c | 141 +++++++++++++++++++++++++++++
arch/x86/kvm/mmu/rmap.h | 34 +++++++
6 files changed, 179 insertions(+), 152 deletions(-)
create mode 100644 arch/x86/kvm/mmu/rmap.c
create mode 100644 arch/x86/kvm/mmu/rmap.h
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 80e3fe184d17..9f766eebeddf 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -12,7 +12,7 @@ include $(srctree)/virt/kvm/Makefile.kvm
kvm-y += x86.o emulate.o i8259.o irq.o lapic.o \
i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \
hyperv.o debugfs.o mmu/mmu.o mmu/page_track.o \
- mmu/spte.o
+ mmu/spte.o mmu/rmap.o
ifdef CONFIG_HYPERV
kvm-y += kvm_onhyperv.o
diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c
index c1390357126a..29f692ecd6f3 100644
--- a/arch/x86/kvm/debugfs.c
+++ b/arch/x86/kvm/debugfs.c
@@ -9,6 +9,7 @@
#include "lapic.h"
#include "mmu.h"
#include "mmu/mmu_internal.h"
+#include "mmu/rmap.h"
static int vcpu_get_timer_advance_ns(void *data, u64 *val)
{
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 4736d7849c60..90b3735d6064 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -26,6 +26,7 @@
#include "kvm_emulate.h"
#include "cpuid.h"
#include "spte.h"
+#include "rmap.h"
#include <linux/kvm_host.h>
#include <linux/types.h>
@@ -112,24 +113,6 @@ module_param(dbg, bool, 0644);
#include <trace/events/kvm.h>
-/* make pte_list_desc fit well in cache lines */
-#define PTE_LIST_EXT 14
-
-/*
- * Slight optimization of cacheline layout, by putting `more' and `spte_count'
- * at the start; then accessing it will only use one single cacheline for
- * either full (entries==PTE_LIST_EXT) case or entries<=6.
- */
-struct pte_list_desc {
- struct pte_list_desc *more;
- /*
- * Stores number of entries stored in the pte_list_desc. No need to be
- * u64 but just for easier alignment. When PTE_LIST_EXT, means full.
- */
- u64 spte_count;
- u64 *sptes[PTE_LIST_EXT];
-};
-
struct kvm_shadow_walk_iterator {
u64 addr;
hpa_t shadow_addr;
@@ -155,7 +138,6 @@ struct kvm_shadow_walk_iterator {
({ spte = mmu_spte_get_lockless(_walker.sptep); 1; }); \
__shadow_walk_next(&(_walker), spte))
-static struct kmem_cache *pte_list_desc_cache;
struct kmem_cache *mmu_page_header_cache;
static struct percpu_counter kvm_total_used_mmu_pages;
@@ -674,11 +656,6 @@ static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
}
-static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
-{
- kmem_cache_free(pte_list_desc_cache, pte_list_desc);
-}
-
static bool sp_has_gptes(struct kvm_mmu_page *sp);
static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
@@ -878,111 +855,6 @@ gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
return slot;
}
-/*
- * About rmap_head encoding:
- *
- * If the bit zero of rmap_head->val is clear, then it points to the only spte
- * in this rmap chain. Otherwise, (rmap_head->val & ~1) points to a struct
- * pte_list_desc containing more mappings.
- */
-
-/*
- * Returns the number of pointers in the rmap chain, not counting the new one.
- */
-static int pte_list_add(struct kvm_mmu_memory_cache *cache, u64 *spte,
- struct kvm_rmap_head *rmap_head)
-{
- struct pte_list_desc *desc;
- int count = 0;
-
- if (!rmap_head->val) {
- rmap_printk("%p %llx 0->1\n", spte, *spte);
- rmap_head->val = (unsigned long)spte;
- } else if (!(rmap_head->val & 1)) {
- rmap_printk("%p %llx 1->many\n", spte, *spte);
- desc = kvm_mmu_memory_cache_alloc(cache);
- desc->sptes[0] = (u64 *)rmap_head->val;
- desc->sptes[1] = spte;
- desc->spte_count = 2;
- rmap_head->val = (unsigned long)desc | 1;
- ++count;
- } else {
- rmap_printk("%p %llx many->many\n", spte, *spte);
- desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
- while (desc->spte_count == PTE_LIST_EXT) {
- count += PTE_LIST_EXT;
- if (!desc->more) {
- desc->more = kvm_mmu_memory_cache_alloc(cache);
- desc = desc->more;
- desc->spte_count = 0;
- break;
- }
- desc = desc->more;
- }
- count += desc->spte_count;
- desc->sptes[desc->spte_count++] = spte;
- }
- return count;
-}
-
-static void
-pte_list_desc_remove_entry(struct kvm_rmap_head *rmap_head,
- struct pte_list_desc *desc, int i,
- struct pte_list_desc *prev_desc)
-{
- int j = desc->spte_count - 1;
-
- desc->sptes[i] = desc->sptes[j];
- desc->sptes[j] = NULL;
- desc->spte_count--;
- if (desc->spte_count)
- return;
- if (!prev_desc && !desc->more)
- rmap_head->val = 0;
- else
- if (prev_desc)
- prev_desc->more = desc->more;
- else
- rmap_head->val = (unsigned long)desc->more | 1;
- mmu_free_pte_list_desc(desc);
-}
-
-static void pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head)
-{
- struct pte_list_desc *desc;
- struct pte_list_desc *prev_desc;
- int i;
-
- if (!rmap_head->val) {
- pr_err("%s: %p 0->BUG\n", __func__, spte);
- BUG();
- } else if (!(rmap_head->val & 1)) {
- rmap_printk("%p 1->0\n", spte);
- if ((u64 *)rmap_head->val != spte) {
- pr_err("%s: %p 1->BUG\n", __func__, spte);
- BUG();
- }
- rmap_head->val = 0;
- } else {
- rmap_printk("%p many->many\n", spte);
- desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
- prev_desc = NULL;
- while (desc) {
- for (i = 0; i < desc->spte_count; ++i) {
- if (desc->sptes[i] == spte) {
- pte_list_desc_remove_entry(rmap_head,
- desc, i, prev_desc);
- return;
- }
- }
- prev_desc = desc;
- desc = desc->more;
- }
- pr_err("%s: %p many->many\n", __func__, spte);
- BUG();
- }
-}
-
static void kvm_zap_one_rmap_spte(struct kvm *kvm,
struct kvm_rmap_head *rmap_head, u64 *sptep)
{
@@ -1011,7 +883,7 @@ static bool kvm_zap_all_rmap_sptes(struct kvm *kvm,
for (i = 0; i < desc->spte_count; i++)
mmu_spte_clear_track_bits(kvm, desc->sptes[i]);
next = desc->more;
- mmu_free_pte_list_desc(desc);
+ free_pte_list_desc(desc);
}
out:
/* rmap_head is meaningless now, remember to reset it */
@@ -1019,26 +891,6 @@ static bool kvm_zap_all_rmap_sptes(struct kvm *kvm,
return true;
}
-unsigned int pte_list_count(struct kvm_rmap_head *rmap_head)
-{
- struct pte_list_desc *desc;
- unsigned int count = 0;
-
- if (!rmap_head->val)
- return 0;
- else if (!(rmap_head->val & 1))
- return 1;
-
- desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
-
- while (desc) {
- count += desc->spte_count;
- desc = desc->more;
- }
-
- return count;
-}
-
static struct kvm_rmap_head *gfn_to_rmap(gfn_t gfn, int level,
const struct kvm_memory_slot *slot)
{
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index dbaf6755c5a7..cd1c8f32269d 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -166,7 +166,6 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
int min_level);
void kvm_flush_remote_tlbs_with_address(struct kvm *kvm,
u64 start_gfn, u64 pages);
-unsigned int pte_list_count(struct kvm_rmap_head *rmap_head);
extern int nx_huge_pages;
static inline bool is_nx_huge_page_enabled(struct kvm *kvm)
diff --git a/arch/x86/kvm/mmu/rmap.c b/arch/x86/kvm/mmu/rmap.c
new file mode 100644
index 000000000000..daa99dee0709
--- /dev/null
+++ b/arch/x86/kvm/mmu/rmap.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "mmu.h"
+#include "mmu_internal.h"
+#include "mmutrace.h"
+#include "rmap.h"
+#include "spte.h"
+
+#include <asm/cmpxchg.h>
+#include <trace/events/kvm.h>
+
+/*
+ * About rmap_head encoding:
+ *
+ * If the bit zero of rmap_head->val is clear, then it points to the only spte
+ * in this rmap chain. Otherwise, (rmap_head->val & ~1) points to a struct
+ * pte_list_desc containing more mappings.
+ */
+
+/*
+ * Returns the number of pointers in the rmap chain, not counting the new one.
+ */
+int pte_list_add(struct kvm_mmu_memory_cache *cache, u64 *spte,
+ struct kvm_rmap_head *rmap_head)
+{
+ struct pte_list_desc *desc;
+ int count = 0;
+
+ if (!rmap_head->val) {
+ rmap_printk("%p %llx 0->1\n", spte, *spte);
+ rmap_head->val = (unsigned long)spte;
+ } else if (!(rmap_head->val & 1)) {
+ rmap_printk("%p %llx 1->many\n", spte, *spte);
+ desc = kvm_mmu_memory_cache_alloc(cache);
+ desc->sptes[0] = (u64 *)rmap_head->val;
+ desc->sptes[1] = spte;
+ desc->spte_count = 2;
+ rmap_head->val = (unsigned long)desc | 1;
+ ++count;
+ } else {
+ rmap_printk("%p %llx many->many\n", spte, *spte);
+ desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+ while (desc->spte_count == PTE_LIST_EXT) {
+ count += PTE_LIST_EXT;
+ if (!desc->more) {
+ desc->more = kvm_mmu_memory_cache_alloc(cache);
+ desc = desc->more;
+ desc->spte_count = 0;
+ break;
+ }
+ desc = desc->more;
+ }
+ count += desc->spte_count;
+ desc->sptes[desc->spte_count++] = spte;
+ }
+ return count;
+}
+
+void free_pte_list_desc(struct pte_list_desc *pte_list_desc)
+{
+ kmem_cache_free(pte_list_desc_cache, pte_list_desc);
+}
+
+static void
+pte_list_desc_remove_entry(struct kvm_rmap_head *rmap_head,
+ struct pte_list_desc *desc, int i,
+ struct pte_list_desc *prev_desc)
+{
+ int j = desc->spte_count - 1;
+
+ desc->sptes[i] = desc->sptes[j];
+ desc->sptes[j] = NULL;
+ desc->spte_count--;
+ if (desc->spte_count)
+ return;
+ if (!prev_desc && !desc->more)
+ rmap_head->val = 0;
+ else
+ if (prev_desc)
+ prev_desc->more = desc->more;
+ else
+ rmap_head->val = (unsigned long)desc->more | 1;
+ free_pte_list_desc(desc);
+}
+
+void pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head)
+{
+ struct pte_list_desc *desc;
+ struct pte_list_desc *prev_desc;
+ int i;
+
+ if (!rmap_head->val) {
+ pr_err("%s: %p 0->BUG\n", __func__, spte);
+ BUG();
+ } else if (!(rmap_head->val & 1)) {
+ rmap_printk("%p 1->0\n", spte);
+ if ((u64 *)rmap_head->val != spte) {
+ pr_err("%s: %p 1->BUG\n", __func__, spte);
+ BUG();
+ }
+ rmap_head->val = 0;
+ } else {
+ rmap_printk("%p many->many\n", spte);
+ desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+ prev_desc = NULL;
+ while (desc) {
+ for (i = 0; i < desc->spte_count; ++i) {
+ if (desc->sptes[i] == spte) {
+ pte_list_desc_remove_entry(rmap_head,
+ desc, i, prev_desc);
+ return;
+ }
+ }
+ prev_desc = desc;
+ desc = desc->more;
+ }
+ pr_err("%s: %p many->many\n", __func__, spte);
+ BUG();
+ }
+}
+
+unsigned int pte_list_count(struct kvm_rmap_head *rmap_head)
+{
+ struct pte_list_desc *desc;
+ unsigned int count = 0;
+
+ if (!rmap_head->val)
+ return 0;
+ else if (!(rmap_head->val & 1))
+ return 1;
+
+ desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+
+ while (desc) {
+ count += desc->spte_count;
+ desc = desc->more;
+ }
+
+ return count;
+}
+
diff --git a/arch/x86/kvm/mmu/rmap.h b/arch/x86/kvm/mmu/rmap.h
new file mode 100644
index 000000000000..059765b6e066
--- /dev/null
+++ b/arch/x86/kvm/mmu/rmap.h
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef __KVM_X86_MMU_RMAP_H
+#define __KVM_X86_MMU_RMAP_H
+
+#include <linux/kvm_host.h>
+
+/* make pte_list_desc fit well in cache lines */
+#define PTE_LIST_EXT 14
+
+/*
+ * Slight optimization of cacheline layout, by putting `more' and `spte_count'
+ * at the start; then accessing it will only use one single cacheline for
+ * either full (entries==PTE_LIST_EXT) case or entries<=6.
+ */
+struct pte_list_desc {
+ struct pte_list_desc *more;
+ /*
+ * Stores number of entries stored in the pte_list_desc. No need to be
+ * u64 but just for easier alignment. When PTE_LIST_EXT, means full.
+ */
+ u64 spte_count;
+ u64 *sptes[PTE_LIST_EXT];
+};
+
+static struct kmem_cache *pte_list_desc_cache;
+
+int pte_list_add(struct kvm_mmu_memory_cache *cache, u64 *spte,
+ struct kvm_rmap_head *rmap_head);
+void free_pte_list_desc(struct pte_list_desc *pte_list_desc);
+void pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head);
+unsigned int pte_list_count(struct kvm_rmap_head *rmap_head);
+
+#endif /* __KVM_X86_MMU_RMAP_H */
--
2.39.0.rc0.267.gcb52ba06e7-goog
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