stage2_pte_cacheable() tries to figure out whether the mapping installed in its 'pte' parameter is cacheable or not. Unfortunately, it fails miserably because it extracts the memory attributes from the entry using FIELD_GET(), which returns the attributes shifted down to bit 0, but then compares this with the unshifted value generated by the PAGE_S2_MEMATTR() macro.
A direct consequence of this bug is that cache maintenance is silently skipped, which in turn causes 32-bit guests to crash early on when their set/way maintenance is trapped but not emulated correctly. Fix the broken masks by avoiding the use of FIELD_GET() altogether. Cc: Quentin Perret <[email protected]> Reported-by: Marc Zyngier <[email protected]> Fixes: 6d9d2115c480 ("KVM: arm64: Add support for stage-2 map()/unmap() in generic page-table") Signed-off-by: Will Deacon <[email protected]> --- Applies on top of the other pgtable fix I previously sent here: https://lore.kernel.org/r/[email protected] arch/arm64/kvm/hyp/pgtable.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 95141b0d6088..0271b4a3b9fe 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -635,7 +635,7 @@ static void stage2_flush_dcache(void *addr, u64 size) static bool stage2_pte_cacheable(kvm_pte_t pte) { - u64 memattr = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR, pte); + u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR; return memattr == PAGE_S2_MEMATTR(NORMAL); } -- 2.29.1.341.ge80a0c044ae-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
