From: Marc Zyngier <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit 04b8dc85bf4a64517e3cf20e409eeaa503b15cc1 upstream. 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 <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Signed-off-by: Christoffer Dall <[email protected]> Signed-off-by: Shannon Zhao <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- arch/arm/include/asm/kvm_mmu.h | 2 ++ arch/arm/kvm/mmu.c | 6 +++--- arch/arm64/include/asm/kvm_mmu.h | 2 ++ 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index 8cd885699420..7a1d664fa13f 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -106,6 +106,8 @@ static inline void kvm_set_s2pte_writable(pte_t *pte) (__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); diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index a79baa59fe15..87a2769898ac 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -177,7 +177,7 @@ 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); unmap_puds(kvm, pgd, addr, next); @@ -236,7 +236,7 @@ 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); @@ -624,7 +624,7 @@ static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache, pte_t *pte, old_pte; /* Create 2nd stage page table mapping - Level 1 */ - 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 6e127e7ca687..0c661b823576 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -106,6 +106,8 @@ static inline void kvm_set_s2pte_writable(pte_t *pte) #define kvm_pud_addr_end(addr, end) pud_addr_end(addr, end) #define kvm_pmd_addr_end(addr, end) pmd_addr_end(addr, end) +#define kvm_pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_S2_PGD - 1)) + static inline bool kvm_page_empty(void *ptr) { struct page *ptr_page = virt_to_page(ptr); -- 2.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
