On Wed, Feb 25, 2015 at 04:55:39PM +0000, Marc Zyngier wrote: > 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. > > Signed-off-by: Marc Zyngier <[email protected]> > --- > arch/arm/include/asm/kvm_mmu.h | 3 ++- > arch/arm/kvm/mmu.c | 8 ++++---- > arch/arm64/include/asm/kvm_mmu.h | 2 ++ > 3 files changed, 8 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h > index 1cac89b..ec669a6 100644 > --- a/arch/arm/include/asm/kvm_mmu.h > +++ b/arch/arm/include/asm/kvm_mmu.h > @@ -149,13 +149,14 @@ static inline bool kvm_s2pmd_readonly(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(kvm, ptep) kvm_page_empty(ptep) > #define kvm_pmd_table_empty(kvm, pmdp) kvm_page_empty(pmdp) > #define kvm_pud_table_empty(kvm, pudp) (0) > diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c > index a6a8252..39a0903 100644 > --- a/arch/arm/kvm/mmu.c > +++ b/arch/arm/kvm/mmu.c > @@ -290,7 +290,7 @@ 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)) > @@ -355,7 +355,7 @@ 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); > @@ -799,7 +799,7 @@ static pud_t *stage2_get_pud(struct kvm *kvm, struct > kvm_mmu_memory_cache *cache > pgd_t *pgd; > pud_t *pud; > > - pgd = kvm->arch.pgd + pgd_index(addr); > + pgd = kvm->arch.pgd + kvm_pgd_index(addr); > if (WARN_ON(pgd_none(*pgd))) { > if (!cache) > return NULL; > @@ -1089,7 +1089,7 @@ static void stage2_wp_range(struct kvm *kvm, > phys_addr_t addr, phys_addr_t end) > pgd_t *pgd; > phys_addr_t next; > > - pgd = kvm->arch.pgd + pgd_index(addr); > + pgd = kvm->arch.pgd + kvm_pgd_index(addr); > do { > /* > * Release kvm_mmu_lock periodically if the memory region is > diff --git a/arch/arm64/include/asm/kvm_mmu.h > b/arch/arm64/include/asm/kvm_mmu.h > index 06c733a..c6300fd 100644 > --- a/arch/arm64/include/asm/kvm_mmu.h > +++ b/arch/arm64/include/asm/kvm_mmu.h > @@ -158,6 +158,8 @@ static inline bool kvm_s2pmd_readonly(pmd_t *pmd) > #define PTRS_PER_S2_PGD (1 << PTRS_PER_S2_PGD_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)) > + > /* > * If we are concatenating first level stage-2 page tables, we would have > less > * than or equal to 16 pointers in the fake PGD, because that's what the > -- > 2.1.4 >
Reviewed-by: Christoffer Dall <[email protected]> _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
