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KVM: Move gfn_to_page out of kmap/unmap pairs
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gfn_to_page might sleep with swap support. Move it out of the kmap calls.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
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Shaohua Li authored and Avi Kivity committed Oct 13, 2007
1 parent 9ae0448 commit fe55188
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Showing 4 changed files with 52 additions and 39 deletions.
2 changes: 1 addition & 1 deletion drivers/kvm/kvm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -599,7 +599,7 @@ int kvm_write_guest(struct kvm_vcpu *vcpu,
unsigned long segment_base(u16 selector);

void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *old, const u8 *new, int bytes);
const u8 *new, int bytes);
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva);
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
int kvm_mmu_load(struct kvm_vcpu *vcpu);
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7 changes: 3 additions & 4 deletions drivers/kvm/kvm_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1076,7 +1076,6 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
{
struct page *page;
void *virt;
unsigned offset = offset_in_page(gpa);

if (((gpa + bytes - 1) >> PAGE_SHIFT) != (gpa >> PAGE_SHIFT))
return 0;
Expand All @@ -1085,7 +1084,7 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
return 0;
mark_page_dirty(vcpu->kvm, gpa >> PAGE_SHIFT);
virt = kmap_atomic(page, KM_USER0);
kvm_mmu_pte_write(vcpu, gpa, virt + offset, val, bytes);
kvm_mmu_pte_write(vcpu, gpa, val, bytes);
memcpy(virt + offset_in_page(gpa), val, bytes);
kunmap_atomic(virt, KM_USER0);
return 1;
Expand Down Expand Up @@ -1455,7 +1454,7 @@ static int vcpu_register_para(struct kvm_vcpu *vcpu, gpa_t para_state_gpa)

mark_page_dirty(vcpu->kvm, para_state_gpa >> PAGE_SHIFT);
para_state_page = pfn_to_page(para_state_hpa >> PAGE_SHIFT);
para_state = kmap_atomic(para_state_page, KM_USER0);
para_state = kmap(para_state_page);

printk(KERN_DEBUG ".... guest version: %d\n", para_state->guest_version);
printk(KERN_DEBUG ".... size: %d\n", para_state->size);
Expand Down Expand Up @@ -1491,7 +1490,7 @@ static int vcpu_register_para(struct kvm_vcpu *vcpu, gpa_t para_state_gpa)

para_state->ret = 0;
err_kunmap_skip:
kunmap_atomic(para_state, KM_USER0);
kunmap(para_state_page);
return 0;
err_gp:
return 1;
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2 changes: 1 addition & 1 deletion drivers/kvm/mmu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1124,7 +1124,7 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
}

void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *old, const u8 *new, int bytes)
const u8 *new, int bytes)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
struct kvm_mmu_page *page;
Expand Down
80 changes: 47 additions & 33 deletions drivers/kvm/paging_tmpl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,10 @@ struct guest_walker {
int level;
gfn_t table_gfn[PT_MAX_FULL_LEVELS];
pt_element_t *table;
pt_element_t pte;
pt_element_t *ptep;
struct page *page;
int index;
pt_element_t inherited_ar;
gfn_t gfn;
u32 error_code;
Expand All @@ -80,11 +83,14 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
pgprintk("%s: addr %lx\n", __FUNCTION__, addr);
walker->level = vcpu->mmu.root_level;
walker->table = NULL;
walker->page = NULL;
walker->ptep = NULL;
root = vcpu->cr3;
#if PTTYPE == 64
if (!is_long_mode(vcpu)) {
walker->ptep = &vcpu->pdptrs[(addr >> 30) & 3];
root = *walker->ptep;
walker->pte = root;
if (!(root & PT_PRESENT_MASK))
goto not_present;
--walker->level;
Expand All @@ -96,7 +102,8 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
walker->level - 1, table_gfn);
slot = gfn_to_memslot(vcpu->kvm, table_gfn);
hpa = safe_gpa_to_hpa(vcpu, root & PT64_BASE_ADDR_MASK);
walker->table = kmap_atomic(pfn_to_page(hpa >> PAGE_SHIFT), KM_USER0);
walker->page = pfn_to_page(hpa >> PAGE_SHIFT);
walker->table = kmap_atomic(walker->page, KM_USER0);

ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) ||
(vcpu->cr3 & CR3_NONPAE_RESERVED_BITS) == 0);
Expand All @@ -108,6 +115,7 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
hpa_t paddr;

ptep = &walker->table[index];
walker->index = index;
ASSERT(((unsigned long)walker->table & PAGE_MASK) ==
((unsigned long)ptep & PAGE_MASK));

Expand Down Expand Up @@ -148,16 +156,20 @@ static int FNAME(walk_addr)(struct guest_walker *walker,

walker->inherited_ar &= walker->table[index];
table_gfn = (*ptep & PT_BASE_ADDR_MASK) >> PAGE_SHIFT;
paddr = safe_gpa_to_hpa(vcpu, *ptep & PT_BASE_ADDR_MASK);
kunmap_atomic(walker->table, KM_USER0);
walker->table = kmap_atomic(pfn_to_page(paddr >> PAGE_SHIFT),
KM_USER0);
paddr = safe_gpa_to_hpa(vcpu, table_gfn << PAGE_SHIFT);
walker->page = pfn_to_page(paddr >> PAGE_SHIFT);
walker->table = kmap_atomic(walker->page, KM_USER0);
--walker->level;
walker->table_gfn[walker->level - 1 ] = table_gfn;
pgprintk("%s: table_gfn[%d] %lx\n", __FUNCTION__,
walker->level - 1, table_gfn);
}
walker->ptep = ptep;
walker->pte = *ptep;
if (walker->page)
walker->ptep = NULL;
if (walker->table)
kunmap_atomic(walker->table, KM_USER0);
pgprintk("%s: pte %llx\n", __FUNCTION__, (u64)*ptep);
return 1;

Expand All @@ -175,13 +187,9 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
walker->error_code |= PFERR_USER_MASK;
if (fetch_fault)
walker->error_code |= PFERR_FETCH_MASK;
return 0;
}

static void FNAME(release_walker)(struct guest_walker *walker)
{
if (walker->table)
kunmap_atomic(walker->table, KM_USER0);
return 0;
}

static void FNAME(mark_pagetable_dirty)(struct kvm *kvm,
Expand All @@ -193,7 +201,7 @@ static void FNAME(mark_pagetable_dirty)(struct kvm *kvm,
static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
u64 *shadow_pte,
gpa_t gaddr,
pt_element_t *gpte,
pt_element_t gpte,
u64 access_bits,
int user_fault,
int write_fault,
Expand All @@ -202,23 +210,34 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
gfn_t gfn)
{
hpa_t paddr;
int dirty = *gpte & PT_DIRTY_MASK;
int dirty = gpte & PT_DIRTY_MASK;
u64 spte = *shadow_pte;
int was_rmapped = is_rmap_pte(spte);

pgprintk("%s: spte %llx gpte %llx access %llx write_fault %d"
" user_fault %d gfn %lx\n",
__FUNCTION__, spte, (u64)*gpte, access_bits,
__FUNCTION__, spte, (u64)gpte, access_bits,
write_fault, user_fault, gfn);

if (write_fault && !dirty) {
*gpte |= PT_DIRTY_MASK;
pt_element_t *guest_ent, *tmp = NULL;

if (walker->ptep)
guest_ent = walker->ptep;
else {
tmp = kmap_atomic(walker->page, KM_USER0);
guest_ent = &tmp[walker->index];
}

*guest_ent |= PT_DIRTY_MASK;
if (!walker->ptep)
kunmap_atomic(tmp, KM_USER0);
dirty = 1;
FNAME(mark_pagetable_dirty)(vcpu->kvm, walker);
}

spte |= PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_DIRTY_MASK;
spte |= *gpte & PT64_NX_MASK;
spte |= gpte & PT64_NX_MASK;
if (!dirty)
access_bits &= ~PT_WRITABLE_MASK;

Expand Down Expand Up @@ -273,13 +292,13 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
rmap_add(vcpu, shadow_pte);
}

static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t *gpte,
static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t gpte,
u64 *shadow_pte, u64 access_bits,
int user_fault, int write_fault, int *ptwrite,
struct guest_walker *walker, gfn_t gfn)
{
access_bits &= *gpte;
FNAME(set_pte_common)(vcpu, shadow_pte, *gpte & PT_BASE_ADDR_MASK,
access_bits &= gpte;
FNAME(set_pte_common)(vcpu, shadow_pte, gpte & PT_BASE_ADDR_MASK,
gpte, access_bits, user_fault, write_fault,
ptwrite, walker, gfn);
}
Expand All @@ -295,22 +314,22 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK))
return;
pgprintk("%s: gpte %llx spte %p\n", __FUNCTION__, (u64)gpte, spte);
FNAME(set_pte)(vcpu, &gpte, spte, PT_USER_MASK | PT_WRITABLE_MASK, 0,
FNAME(set_pte)(vcpu, gpte, spte, PT_USER_MASK | PT_WRITABLE_MASK, 0,
0, NULL, NULL,
(gpte & PT_BASE_ADDR_MASK) >> PAGE_SHIFT);
}

static void FNAME(set_pde)(struct kvm_vcpu *vcpu, pt_element_t *gpde,
static void FNAME(set_pde)(struct kvm_vcpu *vcpu, pt_element_t gpde,
u64 *shadow_pte, u64 access_bits,
int user_fault, int write_fault, int *ptwrite,
struct guest_walker *walker, gfn_t gfn)
{
gpa_t gaddr;

access_bits &= *gpde;
access_bits &= gpde;
gaddr = (gpa_t)gfn << PAGE_SHIFT;
if (PTTYPE == 32 && is_cpuid_PSE36())
gaddr |= (*gpde & PT32_DIR_PSE36_MASK) <<
gaddr |= (gpde & PT32_DIR_PSE36_MASK) <<
(32 - PT32_DIR_PSE36_SHIFT);
FNAME(set_pte_common)(vcpu, shadow_pte, gaddr,
gpde, access_bits, user_fault, write_fault,
Expand All @@ -328,9 +347,8 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
int level;
u64 *shadow_ent;
u64 *prev_shadow_ent = NULL;
pt_element_t *guest_ent = walker->ptep;

if (!is_present_pte(*guest_ent))
if (!is_present_pte(walker->pte))
return NULL;

shadow_addr = vcpu->mmu.root_hpa;
Expand Down Expand Up @@ -364,12 +382,12 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
if (level - 1 == PT_PAGE_TABLE_LEVEL
&& walker->level == PT_DIRECTORY_LEVEL) {
metaphysical = 1;
hugepage_access = *guest_ent;
hugepage_access = walker->pte;
hugepage_access &= PT_USER_MASK | PT_WRITABLE_MASK;
if (*guest_ent & PT64_NX_MASK)
if (walker->pte & PT64_NX_MASK)
hugepage_access |= (1 << 2);
hugepage_access >>= PT_WRITABLE_SHIFT;
table_gfn = (*guest_ent & PT_BASE_ADDR_MASK)
table_gfn = (walker->pte & PT_BASE_ADDR_MASK)
>> PAGE_SHIFT;
} else {
metaphysical = 0;
Expand All @@ -386,12 +404,12 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
}

if (walker->level == PT_DIRECTORY_LEVEL) {
FNAME(set_pde)(vcpu, guest_ent, shadow_ent,
FNAME(set_pde)(vcpu, walker->pte, shadow_ent,
walker->inherited_ar, user_fault, write_fault,
ptwrite, walker, walker->gfn);
} else {
ASSERT(walker->level == PT_PAGE_TABLE_LEVEL);
FNAME(set_pte)(vcpu, guest_ent, shadow_ent,
FNAME(set_pte)(vcpu, walker->pte, shadow_ent,
walker->inherited_ar, user_fault, write_fault,
ptwrite, walker, walker->gfn);
}
Expand Down Expand Up @@ -442,7 +460,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
if (!r) {
pgprintk("%s: guest page fault\n", __FUNCTION__);
inject_page_fault(vcpu, addr, walker.error_code);
FNAME(release_walker)(&walker);
vcpu->last_pt_write_count = 0; /* reset fork detector */
return 0;
}
Expand All @@ -452,8 +469,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __FUNCTION__,
shadow_pte, *shadow_pte, write_pt);

FNAME(release_walker)(&walker);

if (!write_pt)
vcpu->last_pt_write_count = 0; /* reset fork detector */

Expand Down Expand Up @@ -482,7 +497,6 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)
gpa |= vaddr & ~PAGE_MASK;
}

FNAME(release_walker)(&walker);
return gpa;
}

Expand Down

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