[PATCH 2/8] kvm: change memslot data structures for multiple hugepage sizes

Joerg Roedel
2009-06-19T13:18:01Z

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
arch/ia64/include/asm/kvm_host.h | 3 +-
arch/powerpc/include/asm/kvm_host.h | 3 +-
arch/x86/include/asm/kvm_host.h | 12 ++++----
arch/x86/kvm/mmu.c | 30 ++++++++++---------
arch/x86/kvm/paging_tmpl.h | 3 +-
include/linux/kvm_host.h | 2 +-
virt/kvm/kvm_main.c | 53 +++++++++++++++++++++++-----------
7 files changed, 65 insertions(+), 41 deletions(-)

diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 9cf1c4b..d9b6325 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -235,7 +235,8 @@ struct kvm_vm_data {
#define KVM_REQ_PTC_G 32
#define KVM_REQ_RESUME 33

-#define KVM_PAGES_PER_HPAGE 1
+#define KVM_NR_PAGE_SIZES 1
+#define KVM_PAGES_PER_HPAGE(x) 1

struct kvm;
struct kvm_vcpu;
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 3625424..10e884e 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -34,7 +34,8 @@
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1

/* We don't currently support large pages. */
-#define KVM_PAGES_PER_HPAGE (1<<31)
+#define KVM_NR_PAGE_SIZES 1
+#define KVM_PAGES_PER_HPAGE(x) (1<<31)

struct kvm;
struct kvm_run;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c7b0cc2..930bac2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -53,12 +53,12 @@
#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)
+/* KVM Hugepage definitions for x86 */
+#define KVM_NR_PAGE_SIZES 2
+#define KVM_HPAGE_SHIFT(x) (PAGE_SHIFT + (((x) - 1) * 9))
+#define KVM_HPAGE_SIZE(x) (1UL << KVM_HPAGE_SHIFT(x))
+#define KVM_HPAGE_MASK(x) (~(KVM_HPAGE_SIZE(x) - 1))
+#define KVM_PAGES_PER_HPAGE(x) (KVM_HPAGE_SIZE(x) / PAGE_SIZE)

#define DE_VECTOR 0
#define DB_VECTOR 1
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index edf3dea..1f24d88 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -394,9 +394,9 @@ 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;
+ idx = (gfn / KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL)) -
+ (slot->base_gfn / KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL));
+ return &slot->lpage_info[0][idx].write_count;
}

static void account_shadowed(struct kvm *kvm, gfn_t gfn)
@@ -485,10 +485,10 @@ static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
if (!lpage)
return &slot->rmap[gfn - slot->base_gfn];

- idx = (gfn / KVM_PAGES_PER_HPAGE) -
- (slot->base_gfn / KVM_PAGES_PER_HPAGE);
+ idx = (gfn / KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL)) -
+ (slot->base_gfn / KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL));

- return &slot->lpage_info[idx].rmap_pde;
+ return &slot->lpage_info[0][idx].rmap_pde;
}

/*
@@ -724,11 +724,11 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
end = start + (memslot->npages << PAGE_SHIFT);
if (hva >= start && hva < end) {
gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
+ int idx = gfn_offset /
+ KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL);
retval |= handler(kvm, &memslot->rmap[gfn_offset]);
retval |= handler(kvm,
- &memslot->lpage_info[
- gfn_offset /
- KVM_PAGES_PER_HPAGE].rmap_pde);
+ &memslot->lpage_info[0][idx].rmap_pde);
}
}

@@ -1852,8 +1852,9 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
pfn_t pfn;
unsigned long mmu_seq;

- if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
- gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ if (is_largepage_backed(vcpu, gfn &
+ ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1))) {
+ gfn &= ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
largepage = 1;
}

@@ -2058,8 +2059,9 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
if (r)
return r;

- if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
- gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ if (is_largepage_backed(vcpu, gfn &
+ ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1))) {
+ gfn &= ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
largepage = 1;
}
mmu_seq = vcpu->kvm->mmu_notifier_seq;
@@ -2461,7 +2463,7 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
- gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ gfn &= ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
vcpu->arch.update_pte.largepage = 1;
}
vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 322e811..53e129c 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -401,7 +401,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,

if (walker.level == PT_DIRECTORY_LEVEL) {
gfn_t large_gfn;
- large_gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE-1);
+ large_gfn = walker.gfn &
+ ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
if (is_largepage_backed(vcpu, large_gfn)) {
walker.gfn = large_gfn;
largepage = 1;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 1b48092..b3fa28f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -103,7 +103,7 @@ struct kvm_memory_slot {
struct {
unsigned long rmap_pde;
int write_count;
- } *lpage_info;
+ } *lpage_info[KVM_NR_PAGE_SIZES - 1];
unsigned long userspace_addr;
int user_alloc;
};
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8939ffa..c5e6d13 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -995,19 +995,25 @@ out:
static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
struct kvm_memory_slot *dont)
{
+ int i;
+
if (!dont || free->rmap != dont->rmap)
vfree(free->rmap);

if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
vfree(free->dirty_bitmap);

- if (!dont || free->lpage_info != dont->lpage_info)
- vfree(free->lpage_info);
+
+ for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
+ if (!dont || free->lpage_info[i] != dont->lpage_info[i]) {
+ vfree(free->lpage_info[i]);
+ free->lpage_info[i] = NULL;
+ }
+ }

free->npages = 0;
free->dirty_bitmap = NULL;
free->rmap = NULL;
- free->lpage_info = NULL;
}

void kvm_free_physmem(struct kvm *kvm)
@@ -1081,7 +1087,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
int r;
gfn_t base_gfn;
unsigned long npages, ugfn;
- unsigned long largepages, i;
+ int lpages;
+ unsigned long i, j;
struct kvm_memory_slot *memslot;
struct kvm_memory_slot old, new;

@@ -1155,33 +1162,45 @@ int __kvm_set_memory_region(struct kvm *kvm,
else
new.userspace_addr = 0;
}
- if (npages && !new.lpage_info) {
- largepages = 1 + (base_gfn + npages - 1) / KVM_PAGES_PER_HPAGE;
- largepages -= base_gfn / KVM_PAGES_PER_HPAGE;
+ if (!npages)
+ goto skip_lpage;

- new.lpage_info = vmalloc(largepages * sizeof(*new.lpage_info));
+ for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
+ int level = i + 2;

- if (!new.lpage_info)
+ if (new.lpage_info[i])
+ continue;
+
+ lpages = 1 + (base_gfn + npages - 1) /
+ KVM_PAGES_PER_HPAGE(level);
+ lpages -= base_gfn / KVM_PAGES_PER_HPAGE(level);
+
+ new.lpage_info[i] = vmalloc(lpages * sizeof(*new.lpage_info[i]));
+
+ if (!new.lpage_info[i])
goto out_free;

- memset(new.lpage_info, 0, largepages * sizeof(*new.lpage_info));
+ memset(new.lpage_info[i], 0,
+ lpages * sizeof(*new.lpage_info[i]));

- 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;
+ if (base_gfn % KVM_PAGES_PER_HPAGE(level))
+ new.lpage_info[i][0].write_count = 1;
+ if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE(level))
+ new.lpage_info[i][lpages - 1].write_count = 1;
ugfn = new.userspace_addr >> PAGE_SHIFT;
/*
* If the gfn and userspace address are not aligned wrt each
* other, or if explicitly asked to, disable large page
* support for this slot
*/
- if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE - 1) ||
+ if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE(level) - 1) ||
!largepages_enabled)
- for (i = 0; i < largepages; ++i)
- new.lpage_info[i].write_count = 1;
+ for (j = 0; j < lpages; ++j)
+ new.lpage_info[i][j].write_count = 1;
}

+skip_lpage:
+
/* Allocate page dirty bitmap if needed */
if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
unsigned dirty_bytes = ALIGN(npages, BITS_PER_LONG) / 8;
--
1.6.3.1