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authorMarc Zyngier <marc.zyngier@arm.com>2015-03-10 19:07:00 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-07-10 10:38:00 -0700
commitec86d15103a9b73c5f1decd2ea7bc12efecaa3c0 (patch)
treea0269f200913c592dc1a249cd33fe02b360b78cd
parent3ef8d0f1fbf99155d6167d279b38c4bd8ed6c73f (diff)
downloadlwn-ec86d15103a9b73c5f1decd2ea7bc12efecaa3c0.tar.gz
lwn-ec86d15103a9b73c5f1decd2ea7bc12efecaa3c0.zip
arm64: KVM: Do not use pgd_index to index stage-2 pgd
commit 04b8dc85bf4a64517e3cf20e409eeaa503b15cc1 upstream. [Since we don't backport commit c647355 (KVM: arm: Add initial dirty page locking support) for linux-3.14.y, there is no stage2_wp_range in arch/arm/kvm/mmu.c. So ignore the change in stage2_wp_range introduced by this patch.] The kernel's pgd_index macro is designed to index a normal, page sized array. KVM is a bit diffferent, as we can use concatenated pages to have a bigger address space (for example 40bit IPA with 4kB pages gives us an 8kB PGD. In the above case, the use of pgd_index will always return an index inside the first 4kB, which makes a guest that has memory above 0x8000000000 rather unhappy, as it spins forever in a page fault, whist the host happilly corrupts the lower pgd. The obvious fix is to get our own kvm_pgd_index that does the right thing(tm). Tested on X-Gene with a hacked kvmtool that put memory at a stupidly high address. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm/include/asm/kvm_mmu.h3
-rw-r--r--arch/arm/kvm/mmu.c6
-rw-r--r--arch/arm64/include/asm/kvm_mmu.h2
3 files changed, 7 insertions, 4 deletions
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 9f7923193cda..7d35af3f3752 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -117,13 +117,14 @@ static inline void kvm_set_s2pmd_writable(pmd_t *pmd)
(__boundary - 1 < (end) - 1)? __boundary: (end); \
})
+#define kvm_pgd_index(addr) pgd_index(addr)
+
static inline bool kvm_page_empty(void *ptr)
{
struct page *ptr_page = virt_to_page(ptr);
return page_count(ptr_page) == 1;
}
-
#define kvm_pte_table_empty(ptep) kvm_page_empty(ptep)
#define kvm_pmd_table_empty(pmdp) kvm_page_empty(pmdp)
#define kvm_pud_table_empty(pudp) (0)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 524b4b57f650..c612e37166ad 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -194,7 +194,7 @@ static void unmap_range(struct kvm *kvm, pgd_t *pgdp,
phys_addr_t addr = start, end = start + size;
phys_addr_t next;
- pgd = pgdp + pgd_index(addr);
+ pgd = pgdp + kvm_pgd_index(addr);
do {
next = kvm_pgd_addr_end(addr, end);
if (!pgd_none(*pgd))
@@ -264,7 +264,7 @@ static void stage2_flush_memslot(struct kvm *kvm,
phys_addr_t next;
pgd_t *pgd;
- pgd = kvm->arch.pgd + pgd_index(addr);
+ pgd = kvm->arch.pgd + kvm_pgd_index(addr);
do {
next = kvm_pgd_addr_end(addr, end);
stage2_flush_puds(kvm, pgd, addr, next);
@@ -649,7 +649,7 @@ static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache
pud_t *pud;
pmd_t *pmd;
- pgd = kvm->arch.pgd + pgd_index(addr);
+ pgd = kvm->arch.pgd + kvm_pgd_index(addr);
pud = pud_offset(pgd, addr);
if (pud_none(*pud)) {
if (!cache)
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 0d51874c838f..15a8a861264a 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -69,6 +69,8 @@
#define PTRS_PER_S2_PGD (1 << (KVM_PHYS_SHIFT - PGDIR_SHIFT))
#define S2_PGD_ORDER get_order(PTRS_PER_S2_PGD * sizeof(pgd_t))
+#define kvm_pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_S2_PGD - 1))
+
int create_hyp_mappings(void *from, void *to);
int create_hyp_io_mappings(void *from, void *to, phys_addr_t);
void free_boot_hyp_pgd(void);