Despite KVM not using the contiguous bit for anything related to TLBs, the spec does require that the alignment defined by the contiguous bit for a the page size and the level is enforced. Add the required checks to offset the point where PA and VA merge. Fixes: 61e30b9eef7f ("KVM: arm64: nv: Implement nested Stage-2 page table walk logic") Reported-by: Alexandru Elisei <alexandru.elisei@xxxxxxx> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> --- arch/arm64/include/asm/kvm_nested.h | 22 ++++++++++++++++++++++ arch/arm64/kvm/nested.c | 7 ++----- 2 files changed, 24 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h index 5b06c31035a2..6e163501f13e 100644 --- a/arch/arm64/include/asm/kvm_nested.h +++ b/arch/arm64/include/asm/kvm_nested.h @@ -205,4 +205,26 @@ static inline u64 kvm_encode_nested_level(struct kvm_s2_trans *trans) return FIELD_PREP(KVM_NV_GUEST_MAP_SZ, trans->level); } +/* Adjust alignment for the contiguous bit as per StageOA() */ +#define contiguous_bit_shift(d, wi, l) \ + ({ \ + u8 shift = 0; \ + \ + if ((d) & PTE_CONT) { \ + switch (BIT((wi)->pgshift)) { \ + case SZ_4K: \ + shift = 4; \ + break; \ + case SZ_16K: \ + shift = (l) == 2 ? 5 : 7; \ + break; \ + case SZ_64K: \ + shift = 5; \ + break; \ + } \ + } \ + \ + shift; \ + }) + #endif /* __ARM64_KVM_NESTED_H */ diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index de789e0f1ae9..49a7832a3fb1 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -282,11 +282,6 @@ static int walk_nested_s2_pgd(phys_addr_t ipa, return 1; } - /* - * We don't use the contiguous bit in the stage-2 ptes, so skip check - * for misprogramming of the contiguous bit. - */ - if (check_output_size(wi, desc)) { out->esr = compute_fsc(level, ESR_ELx_FSC_ADDRSZ); out->upper_attr = desc; @@ -299,6 +294,8 @@ static int walk_nested_s2_pgd(phys_addr_t ipa, return 1; } + addr_bottom += contiguous_bit_shift(desc, wi, level); + /* Calculate and return the result */ paddr = (desc & GENMASK_ULL(47, addr_bottom)) | (ipa & GENMASK_ULL(addr_bottom - 1, 0)); -- 2.39.2