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authorMarc Zyngier <marc.zyngier@arm.com>2015-03-10 19:07:00 +0000
committerChristoffer Dall <christoffer.dall@linaro.org>2015-03-11 14:24:36 +0100
commit04b8dc85bf4a64517e3cf20e409eeaa503b15cc1 (patch)
treece074a61824c768147f911152c4af6dfa97ff9eb /arch/arm64/include/asm/kvm_mmu.h
parenta987370f8e7a1677ae385042644326d9cd145a20 (diff)
arm64: KVM: Do not use pgd_index to index stage-2 pgd
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>
Diffstat (limited to 'arch/arm64/include/asm/kvm_mmu.h')
-rw-r--r--arch/arm64/include/asm/kvm_mmu.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index a099cd9cdef8..bbfb600fa822 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