[PATCH 6/8] kvm/mmu: add support for another level to page walker

Joerg Roedel
2009-06-19T13:18:24Z

The page walker may be used with nested paging too when accessing mmio areas.
Make it support the additional page-level too.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
arch/x86/kvm/mmu.c | 6 ++++++
arch/x86/kvm/paging_tmpl.h | 16 ++++++++++++++++
2 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ef2396d..fc0e2fc 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -117,6 +117,11 @@ module_param(oos_shadow, bool, 0644);
#define PT64_DIR_BASE_ADDR_MASK \
(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))

+#define PT64_PDPE_BASE_ADDR_MASK \
+ (PT64_BASE_ADDR_MASK & ~(1ULL << (PAGE_SHIFT + (2 * PT64_LEVEL_BITS))))
+#define PT64_PDPE_OFFSET_MASK \
+ (PT64_BASE_ADDR_MASK & (1ULL << (PAGE_SHIFT + (2 * PT64_LEVEL_BITS))))
+
#define PT32_BASE_ADDR_MASK PAGE_MASK
#define PT32_DIR_BASE_ADDR_MASK \
(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
@@ -130,6 +135,7 @@ module_param(oos_shadow, bool, 0644);
#define PFERR_RSVD_MASK (1U << 3)
#define PFERR_FETCH_MASK (1U << 4)

+#define PT_PDPE_LEVEL 3
#define PT_DIRECTORY_LEVEL 2
#define PT_PAGE_TABLE_LEVEL 1

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 8fbf4e7..54c77be 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -55,6 +55,7 @@

#define gpte_to_gfn FNAME(gpte_to_gfn)
#define gpte_to_gfn_pde FNAME(gpte_to_gfn_pde)
+#define gpte_to_gfn_pdpe FNAME(gpte_to_gfn_pdpe)

/*
* The guest_walker structure emulates the behavior of the hardware page
@@ -81,6 +82,11 @@ static gfn_t gpte_to_gfn_pde(pt_element_t gpte)
return (gpte & PT_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
}

+static gfn_t gpte_to_gfn_pdpe(pt_element_t gpte)
+{
+ return (gpte & PT64_PDPE_BASE_ADDR_MASK) >> PAGE_SHIFT;
+}
+
static bool FNAME(cmpxchg_gpte)(struct kvm *kvm,
gfn_t table_gfn, unsigned index,
pt_element_t orig_pte, pt_element_t new_pte)
@@ -201,6 +207,15 @@ walk:
break;
}

+ if (walker->level == PT_PDPE_LEVEL &&
+ (pte & PT_PAGE_SIZE_MASK) &&
+ is_long_mode(vcpu)) {
+ walker->gfn = gpte_to_gfn_pdpe(pte);
+ walker->gfn += (addr & PT64_PDPE_OFFSET_MASK)
+ >> PAGE_SHIFT;
+ break;
+ }
+
pt_access = pte_access;
--walker->level;
}
@@ -609,4 +624,5 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
#undef PT_MAX_FULL_LEVELS
#undef gpte_to_gfn
#undef gpte_to_gfn_pde
+#undef gpte_to_gfn_pdpe
#undef CMPXCHG
--
1.6.3.1