From: Mark Rutland Date: Tue, 25 Nov 2014 13:27:41 +0000 (+0000) Subject: arm64: sanity checks: ignore ID_MMFR0.AuxReg X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9760270c36a4d2ac640ea6294f4f8634a8b27121;p=linux-beck.git arm64: sanity checks: ignore ID_MMFR0.AuxReg It seems that Cortex-A53 r0p4 added support for AIFSR and ADFSR, and ID_MMFR0.AuxReg has been updated accordingly to report this fact. As Cortex-A53 could be paired with CPUs which do not implement these registers (e.g. all current revisions of Cortex-A57), this may trigger a sanity check failure at boot. The AuxReg value describes the availability of the ACTLR, AIFSR, and ADFSR registers, which are only of use to 32-bit guest OSs, and have IMPLEMENTATION DEFINED contents. Given the nature of these registers it is likely that KVM will need to trap accesses regardless of whether the CPUs are heterogeneous. This patch masks out the ID_MMFR0.AuxReg value from the sanity checks, preventing spurious warnings at boot time. Signed-off-by: Mark Rutland Reported-by: Andre Przywara Cc: Catalin Marinas Acked-by: Will Deacon Cc: Marc Zyngier Cc: Peter Maydell Signed-off-by: Will Deacon --- diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 16d6d032ecf1..01994d4ce0c2 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -144,7 +144,12 @@ static void cpuinfo_sanity_check(struct cpuinfo_arm64 *cur) diff |= CHECK(id_isar3, boot, cur, cpu); diff |= CHECK(id_isar4, boot, cur, cpu); diff |= CHECK(id_isar5, boot, cur, cpu); - diff |= CHECK(id_mmfr0, boot, cur, cpu); + /* + * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and + * ACTLR formats could differ across CPUs and therefore would have to + * be trapped for virtualization anyway. + */ + diff |= CHECK_MASK(id_mmfr0, 0xff0fffff, boot, cur, cpu); diff |= CHECK(id_mmfr1, boot, cur, cpu); diff |= CHECK(id_mmfr2, boot, cur, cpu); diff |= CHECK(id_mmfr3, boot, cur, cpu);