lkml.org 
[lkml]   [2008]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 08/35] KVM: MMU: large page support
Date
From: Marcelo Tosatti <marcelo@kvack.org>

Create large pages mappings if the guest PTE's are marked as such and
the underlying memory is hugetlbfs backed. If the largepage contains
write-protected pages, a large pte is not used.

Gives a consistent 2% improvement for data copies on ram mounted
filesystem, without NPT/EPT.

Anthony measures a 4% improvement on 4-way kernbench, with NPT.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---
arch/x86/kvm/mmu.c | 222 +++++++++++++++++++++++++++++++++++++++-----
arch/x86/kvm/paging_tmpl.h | 32 +++++-
arch/x86/kvm/x86.c | 1 +
include/asm-x86/kvm_host.h | 9 ++
include/linux/kvm_host.h | 5 +
virt/kvm/kvm_main.c | 22 ++++-
6 files changed, 259 insertions(+), 32 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 103d008..1932a3a 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -27,6 +27,7 @@
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/swap.h>
+#include <linux/hugetlb.h>

#include <asm/page.h>
#include <asm/cmpxchg.h>
@@ -211,6 +212,11 @@ static int is_shadow_present_pte(u64 pte)
&& pte != shadow_notrap_nonpresent_pte;
}

+static int is_large_pte(u64 pte)
+{
+ return pte & PT_PAGE_SIZE_MASK;
+}
+
static int is_writeble_pte(unsigned long pte)
{
return pte & PT_WRITABLE_MASK;
@@ -350,16 +356,100 @@ static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
}

/*
+ * Return the pointer to the largepage write count for a given
+ * gfn, handling slots that are not large page aligned.
+ */
+static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
+{
+ unsigned long idx;
+
+ idx = (gfn / KVM_PAGES_PER_HPAGE) -
+ (slot->base_gfn / KVM_PAGES_PER_HPAGE);
+ return &slot->lpage_info[idx].write_count;
+}
+
+static void account_shadowed(struct kvm *kvm, gfn_t gfn)
+{
+ int *write_count;
+
+ write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
+ *write_count += 1;
+ WARN_ON(*write_count > KVM_PAGES_PER_HPAGE);
+}
+
+static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
+{
+ int *write_count;
+
+ write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
+ *write_count -= 1;
+ WARN_ON(*write_count < 0);
+}
+
+static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
+{
+ struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+ int *largepage_idx;
+
+ if (slot) {
+ largepage_idx = slot_largepage_idx(gfn, slot);
+ return *largepage_idx;
+ }
+
+ return 1;
+}
+
+static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
+{
+ struct vm_area_struct *vma;
+ unsigned long addr;
+
+ addr = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(addr))
+ return 0;
+
+ vma = find_vma(current->mm, addr);
+ if (vma && is_vm_hugetlb_page(vma))
+ return 1;
+
+ return 0;
+}
+
+static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
+{
+ struct kvm_memory_slot *slot;
+
+ if (has_wrprotected_page(vcpu->kvm, large_gfn))
+ return 0;
+
+ if (!host_largepage_backed(vcpu->kvm, large_gfn))
+ return 0;
+
+ slot = gfn_to_memslot(vcpu->kvm, large_gfn);
+ if (slot && slot->dirty_bitmap)
+ return 0;
+
+ return 1;
+}
+
+/*
* Take gfn and return the reverse mapping to it.
* Note: gfn must be unaliased before this function get called
*/

-static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn)
+static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
{
struct kvm_memory_slot *slot;
+ unsigned long idx;

slot = gfn_to_memslot(kvm, gfn);
- return &slot->rmap[gfn - slot->base_gfn];
+ if (!lpage)
+ return &slot->rmap[gfn - slot->base_gfn];
+
+ idx = (gfn / KVM_PAGES_PER_HPAGE) -
+ (slot->base_gfn / KVM_PAGES_PER_HPAGE);
+
+ return &slot->lpage_info[idx].rmap_pde;
}

/*
@@ -371,7 +461,7 @@ static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn)
* If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
* containing more mappings.
*/
-static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
+static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, int lpage)
{
struct kvm_mmu_page *sp;
struct kvm_rmap_desc *desc;
@@ -383,7 +473,7 @@ static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
gfn = unalias_gfn(vcpu->kvm, gfn);
sp = page_header(__pa(spte));
sp->gfns[spte - sp->spt] = gfn;
- rmapp = gfn_to_rmap(vcpu->kvm, gfn);
+ rmapp = gfn_to_rmap(vcpu->kvm, gfn, lpage);
if (!*rmapp) {
rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
*rmapp = (unsigned long)spte;
@@ -449,7 +539,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
kvm_release_page_dirty(page);
else
kvm_release_page_clean(page);
- rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt]);
+ rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte));
if (!*rmapp) {
printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
BUG();
@@ -515,7 +605,7 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
int write_protected = 0;

gfn = unalias_gfn(kvm, gfn);
- rmapp = gfn_to_rmap(kvm, gfn);
+ rmapp = gfn_to_rmap(kvm, gfn, 0);

spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
@@ -528,8 +618,27 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
}
spte = rmap_next(kvm, rmapp, spte);
}
+ /* check for huge page mappings */
+ rmapp = gfn_to_rmap(kvm, gfn, 1);
+ spte = rmap_next(kvm, rmapp, NULL);
+ while (spte) {
+ BUG_ON(!spte);
+ BUG_ON(!(*spte & PT_PRESENT_MASK));
+ BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
+ pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
+ if (is_writeble_pte(*spte)) {
+ rmap_remove(kvm, spte);
+ --kvm->stat.lpages;
+ set_shadow_pte(spte, shadow_trap_nonpresent_pte);
+ write_protected = 1;
+ }
+ spte = rmap_next(kvm, rmapp, spte);
+ }
+
if (write_protected)
kvm_flush_remote_tlbs(kvm);
+
+ account_shadowed(kvm, gfn);
}

#ifdef MMU_DEBUG
@@ -747,11 +856,17 @@ static void kvm_mmu_page_unlink_children(struct kvm *kvm,
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
ent = pt[i];

+ if (is_shadow_present_pte(ent)) {
+ if (!is_large_pte(ent)) {
+ ent &= PT64_BASE_ADDR_MASK;
+ mmu_page_remove_parent_pte(page_header(ent),
+ &pt[i]);
+ } else {
+ --kvm->stat.lpages;
+ rmap_remove(kvm, &pt[i]);
+ }
+ }
pt[i] = shadow_trap_nonpresent_pte;
- if (!is_shadow_present_pte(ent))
- continue;
- ent &= PT64_BASE_ADDR_MASK;
- mmu_page_remove_parent_pte(page_header(ent), &pt[i]);
}
kvm_flush_remote_tlbs(kvm);
}
@@ -791,6 +906,8 @@ static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
}
kvm_mmu_page_unlink_children(kvm, sp);
if (!sp->root_count) {
+ if (!sp->role.metaphysical)
+ unaccount_shadowed(kvm, sp->gfn);
hlist_del(&sp->hash_link);
kvm_mmu_free_page(kvm, sp);
} else {
@@ -894,7 +1011,8 @@ struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
unsigned pt_access, unsigned pte_access,
int user_fault, int write_fault, int dirty,
- int *ptwrite, gfn_t gfn, struct page *page)
+ int *ptwrite, int largepage, gfn_t gfn,
+ struct page *page)
{
u64 spte;
int was_rmapped = 0;
@@ -907,15 +1025,29 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
write_fault, user_fault, gfn);

if (is_rmap_pte(*shadow_pte)) {
- if (host_pfn != page_to_pfn(page)) {
+ /*
+ * If we overwrite a PTE page pointer with a 2MB PMD, unlink
+ * the parent of the now unreachable PTE.
+ */
+ if (largepage && !is_large_pte(*shadow_pte)) {
+ struct kvm_mmu_page *child;
+ u64 pte = *shadow_pte;
+
+ child = page_header(pte & PT64_BASE_ADDR_MASK);
+ mmu_page_remove_parent_pte(child, shadow_pte);
+ } else if (host_pfn != page_to_pfn(page)) {
pgprintk("hfn old %lx new %lx\n",
host_pfn, page_to_pfn(page));
rmap_remove(vcpu->kvm, shadow_pte);
+ } else {
+ if (largepage)
+ was_rmapped = is_large_pte(*shadow_pte);
+ else
+ was_rmapped = 1;
}
- else
- was_rmapped = 1;
}

+
/*
* We don't set the accessed bit, since we sometimes want to see
* whether the guest actually used the pte (in order to detect
@@ -930,6 +1062,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
spte |= PT_PRESENT_MASK;
if (pte_access & ACC_USER_MASK)
spte |= PT_USER_MASK;
+ if (largepage)
+ spte |= PT_PAGE_SIZE_MASK;

spte |= page_to_phys(page);

@@ -944,7 +1078,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
}

shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
- if (shadow) {
+ if (shadow ||
+ (largepage && has_wrprotected_page(vcpu->kvm, gfn))) {
pgprintk("%s: found shadow page for %lx, marking ro\n",
__FUNCTION__, gfn);
pte_access &= ~ACC_WRITE_MASK;
@@ -963,10 +1098,17 @@ unshadowed:
mark_page_dirty(vcpu->kvm, gfn);

pgprintk("%s: setting spte %llx\n", __FUNCTION__, spte);
+ pgprintk("instantiating %s PTE (%s) at %d (%llx) addr %llx\n",
+ (spte&PT_PAGE_SIZE_MASK)? "2MB" : "4kB",
+ (spte&PT_WRITABLE_MASK)?"RW":"R", gfn, spte, shadow_pte);
set_shadow_pte(shadow_pte, spte);
+ if (!was_rmapped && (spte & PT_PAGE_SIZE_MASK)
+ && (spte & PT_PRESENT_MASK))
+ ++vcpu->kvm->stat.lpages;
+
page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
if (!was_rmapped) {
- rmap_add(vcpu, shadow_pte, gfn);
+ rmap_add(vcpu, shadow_pte, gfn, largepage);
if (!is_rmap_pte(*shadow_pte))
kvm_release_page_clean(page);
} else {
@@ -984,7 +1126,8 @@ static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
}

static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
- gfn_t gfn, struct page *page, int level)
+ int largepage, gfn_t gfn, struct page *page,
+ int level)
{
hpa_t table_addr = vcpu->arch.mmu.root_hpa;
int pt_write = 0;
@@ -998,7 +1141,13 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,

if (level == 1) {
mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
- 0, write, 1, &pt_write, gfn, page);
+ 0, write, 1, &pt_write, 0, gfn, page);
+ return pt_write;
+ }
+
+ if (largepage && level == 2) {
+ mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
+ 0, write, 1, &pt_write, 1, gfn, page);
return pt_write;
}

@@ -1027,12 +1176,18 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
{
int r;
+ int largepage = 0;

struct page *page;

down_read(&vcpu->kvm->slots_lock);

down_read(&current->mm->mmap_sem);
+ if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
+ gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ largepage = 1;
+ }
+
page = gfn_to_page(vcpu->kvm, gfn);
up_read(&current->mm->mmap_sem);

@@ -1045,7 +1200,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)

spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
- r = __direct_map(vcpu, v, write, gfn, page, PT32E_ROOT_LEVEL);
+ r = __direct_map(vcpu, v, write, largepage, gfn, page,
+ PT32E_ROOT_LEVEL);
spin_unlock(&vcpu->kvm->mmu_lock);

up_read(&vcpu->kvm->slots_lock);
@@ -1180,6 +1336,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
{
struct page *page;
int r;
+ int largepage = 0;
+ gfn_t gfn = gpa >> PAGE_SHIFT;

ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
@@ -1189,7 +1347,11 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
return r;

down_read(&current->mm->mmap_sem);
- page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
+ if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
+ gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ largepage = 1;
+ }
+ page = gfn_to_page(vcpu->kvm, gfn);
if (is_error_page(page)) {
kvm_release_page_clean(page);
up_read(&current->mm->mmap_sem);
@@ -1198,7 +1360,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
- gpa >> PAGE_SHIFT, page, TDP_ROOT_LEVEL);
+ largepage, gfn, page, TDP_ROOT_LEVEL);
spin_unlock(&vcpu->kvm->mmu_lock);
up_read(&current->mm->mmap_sem);

@@ -1397,7 +1559,8 @@ static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,

pte = *spte;
if (is_shadow_present_pte(pte)) {
- if (sp->role.level == PT_PAGE_TABLE_LEVEL)
+ if (sp->role.level == PT_PAGE_TABLE_LEVEL ||
+ is_large_pte(pte))
rmap_remove(vcpu->kvm, spte);
else {
child = page_header(pte & PT64_BASE_ADDR_MASK);
@@ -1405,6 +1568,8 @@ static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
}
}
set_shadow_pte(spte, shadow_trap_nonpresent_pte);
+ if (is_large_pte(pte))
+ --vcpu->kvm->stat.lpages;
}

static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
@@ -1412,7 +1577,8 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
u64 *spte,
const void *new)
{
- if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
+ if ((sp->role.level != PT_PAGE_TABLE_LEVEL)
+ && !vcpu->arch.update_pte.largepage) {
++vcpu->kvm->stat.mmu_pde_zapped;
return;
}
@@ -1460,6 +1626,8 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
u64 gpte = 0;
struct page *page;

+ vcpu->arch.update_pte.largepage = 0;
+
if (bytes != 4 && bytes != 8)
return;

@@ -1487,9 +1655,13 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
return;
gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

- down_read(&vcpu->kvm->slots_lock);
+ down_read(&current->mm->mmap_sem);
+ if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
+ gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ vcpu->arch.update_pte.largepage = 1;
+ }
page = gfn_to_page(vcpu->kvm, gfn);
- up_read(&vcpu->kvm->slots_lock);
+ up_read(&current->mm->mmap_sem);

if (is_error_page(page)) {
kvm_release_page_clean(page);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 4b55f46..17f9d16 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -248,6 +248,7 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
pt_element_t gpte;
unsigned pte_access;
struct page *npage;
+ int largepage = vcpu->arch.update_pte.largepage;

gpte = *(const pt_element_t *)pte;
if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) {
@@ -264,7 +265,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
return;
get_page(npage);
mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0,
- gpte & PT_DIRTY_MASK, NULL, gpte_to_gfn(gpte), npage);
+ gpte & PT_DIRTY_MASK, NULL, largepage, gpte_to_gfn(gpte),
+ npage);
}

/*
@@ -272,8 +274,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
*/
static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
struct guest_walker *walker,
- int user_fault, int write_fault, int *ptwrite,
- struct page *page)
+ int user_fault, int write_fault, int largepage,
+ int *ptwrite, struct page *page)
{
hpa_t shadow_addr;
int level;
@@ -301,11 +303,19 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
shadow_ent = ((u64 *)__va(shadow_addr)) + index;
if (level == PT_PAGE_TABLE_LEVEL)
break;
- if (is_shadow_present_pte(*shadow_ent)) {
+
+ if (largepage && level == PT_DIRECTORY_LEVEL)
+ break;
+
+ if (is_shadow_present_pte(*shadow_ent)
+ && !is_large_pte(*shadow_ent)) {
shadow_addr = *shadow_ent & PT64_BASE_ADDR_MASK;
continue;
}

+ if (is_large_pte(*shadow_ent))
+ rmap_remove(vcpu->kvm, shadow_ent);
+
if (level - 1 == PT_PAGE_TABLE_LEVEL
&& walker->level == PT_DIRECTORY_LEVEL) {
metaphysical = 1;
@@ -339,7 +349,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
mmu_set_spte(vcpu, shadow_ent, access, walker->pte_access & access,
user_fault, write_fault,
walker->ptes[walker->level-1] & PT_DIRTY_MASK,
- ptwrite, walker->gfn, page);
+ ptwrite, largepage, walker->gfn, page);

return shadow_ent;
}
@@ -369,6 +379,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
int write_pt = 0;
int r;
struct page *page;
+ int largepage = 0;

pgprintk("%s: addr %lx err %x\n", __FUNCTION__, addr, error_code);
kvm_mmu_audit(vcpu, "pre page fault");
@@ -396,6 +407,14 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
}

down_read(&current->mm->mmap_sem);
+ if (walker.level == PT_DIRECTORY_LEVEL) {
+ gfn_t large_gfn;
+ large_gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE-1);
+ if (is_largepage_backed(vcpu, large_gfn)) {
+ walker.gfn = large_gfn;
+ largepage = 1;
+ }
+ }
page = gfn_to_page(vcpu->kvm, walker.gfn);
up_read(&current->mm->mmap_sem);

@@ -410,7 +429,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
shadow_pte = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
- &write_pt, page);
+ largepage, &write_pt, page);
+
pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __FUNCTION__,
shadow_pte, *shadow_pte, write_pt);

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e8e6492..0458bd5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -88,6 +88,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "mmu_recycled", VM_STAT(mmu_recycled) },
{ "mmu_cache_miss", VM_STAT(mmu_cache_miss) },
{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },
+ { "largepages", VM_STAT(lpages) },
{ NULL }
};

diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 7535839..58291a6 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -38,6 +38,13 @@
#define INVALID_PAGE (~(hpa_t)0)
#define UNMAPPED_GVA (~(gpa_t)0)

+/* shadow tables are PAE even on non-PAE hosts */
+#define KVM_HPAGE_SHIFT 21
+#define KVM_HPAGE_SIZE (1UL << KVM_HPAGE_SHIFT)
+#define KVM_HPAGE_MASK (~(KVM_HPAGE_SIZE - 1))
+
+#define KVM_PAGES_PER_HPAGE (KVM_HPAGE_SIZE / PAGE_SIZE)
+
#define DE_VECTOR 0
#define UD_VECTOR 6
#define NM_VECTOR 7
@@ -229,6 +236,7 @@ struct kvm_vcpu_arch {
struct {
gfn_t gfn; /* presumed gfn during guest pte update */
struct page *page; /* page corresponding to that gfn */
+ int largepage;
} update_pte;

struct i387_fxsave_struct host_fx_image;
@@ -306,6 +314,7 @@ struct kvm_vm_stat {
u32 mmu_recycled;
u32 mmu_cache_miss;
u32 remote_tlb_flush;
+ u32 lpages;
};

struct kvm_vcpu_stat {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 994278f..9750bb3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -103,6 +103,10 @@ struct kvm_memory_slot {
unsigned long flags;
unsigned long *rmap;
unsigned long *dirty_bitmap;
+ struct {
+ unsigned long rmap_pde;
+ int write_count;
+ } *lpage_info;
unsigned long userspace_addr;
int user_alloc;
};
@@ -169,6 +173,7 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
int user_alloc);
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
+unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);
void kvm_release_page_clean(struct page *page);
void kvm_release_page_dirty(struct page *page);
int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c41eb57..0dabf58 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -212,9 +212,13 @@ static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
vfree(free->dirty_bitmap);

+ if (!dont || free->lpage_info != dont->lpage_info)
+ vfree(free->lpage_info);
+
free->npages = 0;
free->dirty_bitmap = NULL;
free->rmap = NULL;
+ free->lpage_info = NULL;
}

void kvm_free_physmem(struct kvm *kvm)
@@ -324,6 +328,22 @@ int __kvm_set_memory_region(struct kvm *kvm,
new.user_alloc = user_alloc;
new.userspace_addr = mem->userspace_addr;
}
+ if (npages && !new.lpage_info) {
+ int largepages = npages / KVM_PAGES_PER_HPAGE;
+ if (npages % KVM_PAGES_PER_HPAGE)
+ largepages++;
+ new.lpage_info = vmalloc(largepages * sizeof(*new.lpage_info));
+
+ if (!new.lpage_info)
+ goto out_free;
+
+ memset(new.lpage_info, 0, largepages * sizeof(*new.lpage_info));
+
+ if (base_gfn % KVM_PAGES_PER_HPAGE)
+ new.lpage_info[0].write_count = 1;
+ if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE)
+ new.lpage_info[largepages-1].write_count = 1;
+ }

/* Allocate page dirty bitmap if needed */
if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
@@ -467,7 +487,7 @@ int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);

-static unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
+unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;

--
1.5.4.5


\
 
 \ /
  Last update: 2008-04-03 21:41    [from the cache]
©2003-2011 Jasper Spaans