From: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Cc: akpm-3NddpPZAyC0@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH 4/33] KVM: MMU: Fold fetch_guest() into init_walker()
Date: Thu, 04 Jan 2007 15:53:05 -0000 [thread overview]
Message-ID: <20070104155305.DC4E1250048@il.qumranet.com> (raw)
In-Reply-To: <459D21DD.5090506-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
It is never necessary to fetch a guest entry from an intermediate page table
level (except for large pages), so avoid some confusion by always descending
into the lowest possible level.
Rename init_walker() to walk_addr() as it is no longer restricted to
initialization.
Signed-off-by: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
Index: linux-2.6/drivers/kvm/paging_tmpl.h
===================================================================
--- linux-2.6.orig/drivers/kvm/paging_tmpl.h
+++ linux-2.6/drivers/kvm/paging_tmpl.h
@@ -54,14 +54,19 @@ struct guest_walker {
int level;
gfn_t table_gfn;
pt_element_t *table;
+ pt_element_t *ptep;
pt_element_t inherited_ar;
};
-static void FNAME(init_walker)(struct guest_walker *walker,
- struct kvm_vcpu *vcpu)
+/*
+ * Fetch a guest pte for a guest virtual address
+ */
+static void FNAME(walk_addr)(struct guest_walker *walker,
+ struct kvm_vcpu *vcpu, gva_t addr)
{
hpa_t hpa;
struct kvm_memory_slot *slot;
+ pt_element_t *ptep;
walker->level = vcpu->mmu.root_level;
walker->table_gfn = (vcpu->cr3 & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
@@ -75,6 +80,38 @@ static void FNAME(init_walker)(struct gu
walker->table = (pt_element_t *)( (unsigned long)walker->table |
(unsigned long)(vcpu->cr3 & ~(PAGE_MASK | CR3_FLAGS_MASK)) );
walker->inherited_ar = PT_USER_MASK | PT_WRITABLE_MASK;
+
+ for (;;) {
+ int index = PT_INDEX(addr, walker->level);
+ hpa_t paddr;
+
+ ptep = &walker->table[index];
+ ASSERT(((unsigned long)walker->table & PAGE_MASK) ==
+ ((unsigned long)ptep & PAGE_MASK));
+
+ /* Don't set accessed bit on PAE PDPTRs */
+ if (vcpu->mmu.root_level != 3 || walker->level != 3)
+ if ((*ptep & (PT_PRESENT_MASK | PT_ACCESSED_MASK))
+ == PT_PRESENT_MASK)
+ *ptep |= PT_ACCESSED_MASK;
+
+ if (!is_present_pte(*ptep) ||
+ walker->level == PT_PAGE_TABLE_LEVEL ||
+ (walker->level == PT_DIRECTORY_LEVEL &&
+ (*ptep & PT_PAGE_SIZE_MASK) &&
+ (PTTYPE == 64 || is_pse(vcpu))))
+ break;
+
+ if (walker->level != 3 || is_long_mode(vcpu))
+ walker->inherited_ar &= walker->table[index];
+ walker->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);
+ --walker->level;
+ }
+ walker->ptep = ptep;
}
static void FNAME(release_walker)(struct guest_walker *walker)
@@ -110,41 +147,6 @@ static void FNAME(set_pde)(struct kvm_vc
}
/*
- * Fetch a guest pte from a specific level in the paging hierarchy.
- */
-static pt_element_t *FNAME(fetch_guest)(struct kvm_vcpu *vcpu,
- struct guest_walker *walker,
- int level,
- gva_t addr)
-{
-
- ASSERT(level > 0 && level <= walker->level);
-
- for (;;) {
- int index = PT_INDEX(addr, walker->level);
- hpa_t paddr;
-
- ASSERT(((unsigned long)walker->table & PAGE_MASK) ==
- ((unsigned long)&walker->table[index] & PAGE_MASK));
- if (level == walker->level ||
- !is_present_pte(walker->table[index]) ||
- (walker->level == PT_DIRECTORY_LEVEL &&
- (walker->table[index] & PT_PAGE_SIZE_MASK) &&
- (PTTYPE == 64 || is_pse(vcpu))))
- return &walker->table[index];
- if (walker->level != 3 || is_long_mode(vcpu))
- walker->inherited_ar &= walker->table[index];
- walker->table_gfn = (walker->table[index] & PT_BASE_ADDR_MASK)
- >> PAGE_SHIFT;
- paddr = safe_gpa_to_hpa(vcpu, walker->table[index] & PT_BASE_ADDR_MASK);
- kunmap_atomic(walker->table, KM_USER0);
- walker->table = kmap_atomic(pfn_to_page(paddr >> PAGE_SHIFT),
- KM_USER0);
- --walker->level;
- }
-}
-
-/*
* Fetch a shadow pte for a specific level in the paging hierarchy.
*/
static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
@@ -153,6 +155,10 @@ static u64 *FNAME(fetch)(struct kvm_vcpu
hpa_t shadow_addr;
int level;
u64 *prev_shadow_ent = NULL;
+ pt_element_t *guest_ent = walker->ptep;
+
+ if (!is_present_pte(*guest_ent))
+ return NULL;
shadow_addr = vcpu->mmu.root_hpa;
level = vcpu->mmu.shadow_root_level;
@@ -160,7 +166,6 @@ static u64 *FNAME(fetch)(struct kvm_vcpu
for (; ; level--) {
u32 index = SHADOW_PT_INDEX(addr, level);
u64 *shadow_ent = ((u64 *)__va(shadow_addr)) + index;
- pt_element_t *guest_ent;
u64 shadow_pte;
if (is_present_pte(*shadow_ent) || is_io_pte(*shadow_ent)) {
@@ -171,21 +176,6 @@ static u64 *FNAME(fetch)(struct kvm_vcpu
continue;
}
- if (PTTYPE == 32 && level > PT32_ROOT_LEVEL) {
- ASSERT(level == PT32E_ROOT_LEVEL);
- guest_ent = FNAME(fetch_guest)(vcpu, walker,
- PT32_ROOT_LEVEL, addr);
- } else
- guest_ent = FNAME(fetch_guest)(vcpu, walker,
- level, addr);
-
- if (!is_present_pte(*guest_ent))
- return NULL;
-
- /* Don't set accessed bit on PAE PDPTRs */
- if (vcpu->mmu.root_level != 3 || walker->level != 3)
- *guest_ent |= PT_ACCESSED_MASK;
-
if (level == PT_PAGE_TABLE_LEVEL) {
if (walker->level == PT_DIRECTORY_LEVEL) {
@@ -253,7 +243,7 @@ static int FNAME(fix_write_pf)(struct kv
*shadow_ent &= ~PT_USER_MASK;
}
- guest_ent = FNAME(fetch_guest)(vcpu, walker, PT_PAGE_TABLE_LEVEL, addr);
+ guest_ent = walker->ptep;
if (!is_present_pte(*guest_ent)) {
*shadow_ent = 0;
@@ -296,7 +286,7 @@ static int FNAME(page_fault)(struct kvm_
* Look up the shadow pte for the faulting address.
*/
for (;;) {
- FNAME(init_walker)(&walker, vcpu);
+ FNAME(walk_addr)(&walker, vcpu, addr);
shadow_pte = FNAME(fetch)(vcpu, addr, &walker);
if (IS_ERR(shadow_pte)) { /* must be -ENOMEM */
nonpaging_flush(vcpu);
@@ -357,9 +347,8 @@ static gpa_t FNAME(gva_to_gpa)(struct kv
pt_element_t guest_pte;
gpa_t gpa;
- FNAME(init_walker)(&walker, vcpu);
- guest_pte = *FNAME(fetch_guest)(vcpu, &walker, PT_PAGE_TABLE_LEVEL,
- vaddr);
+ FNAME(walk_addr)(&walker, vcpu, vaddr);
+ guest_pte = *walker.ptep;
FNAME(release_walker)(&walker);
if (!is_present_pte(guest_pte))
-------------------------------------------------------------------------
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next prev parent reply other threads:[~2007-01-04 15:53 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-04 15:48 [PATCH 0/33] KVM: MMU: Cache shadow page tables Avi Kivity
2007-01-04 15:50 ` [PATCH 1/33] KVM: MMU: Implement simple reverse mapping Avi Kivity
[not found] ` <459D21DD.5090506-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-04 15:51 ` [PATCH 2/33] KVM: MMU: Teach the page table walker to track guest page table gfns Avi Kivity
2007-01-04 15:52 ` [PATCH 3/33] KVM: MMU: Load the pae pdptrs on cr3 change like the processor does Avi Kivity
2007-01-04 15:53 ` Avi Kivity [this message]
2007-01-04 15:54 ` [PATCH 5/33] KVM: MU: Special treatment for shadow pae root pages Avi Kivity
2007-01-04 15:55 ` [PATCH 6/33] KVM: MMU: Use the guest pdptrs instead of mapping cr3 in pae mode Avi Kivity
2007-01-04 15:56 ` [PATCH 7/33] KVM: MMU: Make the shadow page tables also special-case pae Avi Kivity
2007-01-04 15:57 ` [PATCH 8/33] KVM: MMU: Make kvm_mmu_alloc_page() return a kvm_mmu_page pointer Avi Kivity
2007-01-04 15:58 ` [PATCH 9/33] KVM: MMU: Shadow page table caching Avi Kivity
2007-01-04 15:59 ` [PATCH 10/33] KVM: MMU: Write protect guest pages when a shadow is created for them Avi Kivity
2007-01-04 16:00 ` [PATCH 11/33] KVM: MMU: Let the walker extract the target page gfn from the pte Avi Kivity
2007-01-04 16:01 ` [PATCH 12/33] KVM: MMU: Support emulated writes into RAM Avi Kivity
2007-01-04 16:02 ` [PATCH 13/33] KVM: MMU: Zap shadow page table entries on writes to guest page tables Avi Kivity
2007-01-04 16:03 ` [PATCH 14/33] KVM: MMU: If emulating an instruction fails, try unprotecting the page Avi Kivity
2007-01-04 16:04 ` [PATCH 15/33] KVM: MMU: Implement child shadow unlinking Avi Kivity
2007-01-04 16:06 ` [PATCH 17/33] KVM: MMU: oom handling Avi Kivity
2007-01-04 16:07 ` [PATCH 18/33] KVM: MMU: Remove invlpg interception Avi Kivity
2007-01-04 16:08 ` [PATCH 19/33] KVM: MMU: Remove release_pt_page_64() Avi Kivity
2007-01-04 16:10 ` [PATCH 21/33] KVM: MMU: <ove is_empty_shadow_page() above kvm_mmu_free_page() Avi Kivity
2007-01-04 16:11 ` [PATCH 22/33] KVM: MMU: Ensure freed shadow pages are clean Avi Kivity
2007-01-04 16:13 ` [PATCH 24/33] KVM: MMU: Page table write flood protection Avi Kivity
2007-01-04 16:14 ` [PATCH 25/33] KVM: MMU: Never free a shadow page actively serving as a root Avi Kivity
2007-01-04 16:15 ` [PATCH 26/33] KVM: MMU: Fix cmpxchg8b emulation Avi Kivity
2007-01-04 16:16 ` [PATCH 27/33] KVM: MMU: Treat user-mode faults as a hint that a page is no longer a page table Avi Kivity
2007-01-04 16:17 ` [PATCH 28/33] KVM: MMU: Free pages on kvm destruction Avi Kivity
2007-01-04 16:18 ` [PATCH 29/33] KVM: MMU: Replace atomic allocations by preallocated objects Avi Kivity
2007-01-04 16:19 ` [PATCH 30/33] KVM: MMU: Detect oom conditions and propagate error to userspace Avi Kivity
2007-01-04 16:20 ` [PATCH 31/33] KVM: MMU: Flush guest tlb when reducing permissions on a pte Avi Kivity
2007-01-04 16:21 ` [PATCH 32/33] KVM: MMU: Destroy mmu while we still have a vcpu left Avi Kivity
2007-01-04 16:22 ` [PATCH 33/33] KVM: MMU: add audit code to check mappings, etc are correct Avi Kivity
2007-01-04 17:22 ` [PATCH 0/33] KVM: MMU: Cache shadow page tables Andrew Morton
[not found] ` <20070104092226.91fa2dfe.akpm-3NddpPZAyC0@public.gmane.org>
2007-01-04 17:41 ` Avi Kivity
[not found] ` <459D3C65.2090703-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-04 18:02 ` Ingo Molnar
2007-01-04 16:05 ` [PATCH 16/33] KVM: MMU: kvm_mmu_put_page() only removes one link to the page Avi Kivity
2007-01-04 16:09 ` [PATCH 20/33] KVM: MMU: Handle misaligned accesses to write protected guest page tables Avi Kivity
2007-01-04 16:12 ` [PATCH 23/33] KVM: MMU: If an empty shadow page is not empty, report more info Avi Kivity
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