From 9d2179d6f960aef1b8aab4d014fd8385f0a187e5 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 28 Oct 2016 22:51:46 +1100 Subject: ppc: Validate compatibility modes when setting Current ppc_set_compat() will attempt to set any compatiblity mode specified, regardless of whether it's available on the CPU. The caller is expected to make sure it is setting a possible mode, which is awkwward because most of the information to make that decision is at the CPU level. This begins to clean this up by introducing a ppc_check_compat() function which will determine if a given compatiblity mode is supported on a CPU (and also whether it lies within specified minimum and maximum compat levels, which will be useful later). It also contains an assertion that the CPU has a "virtual hypervisor"[1], that is, that the guest isn't permitted to execute hypervisor privilege code. Without that, the guest would own the PCR and so could override any mode set here. Only machine types which use a virtual hypervisor (i.e. 'pseries') should use ppc_check_compat(). ppc_set_compat() is modified to validate the compatibility mode it is given and fail if it's not available on this CPU. [1] Or user-only mode, which also obviously doesn't allow access to the hypervisor privileged PCR. We don't use that now, but could in future. Signed-off-by: David Gibson Reviewed-by: Alexey Kardashevskiy --- target/ppc/cpu.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'target/ppc/cpu.h') diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h index cd76053a0d..22842ddd35 100644 --- a/target/ppc/cpu.h +++ b/target/ppc/cpu.h @@ -1323,6 +1323,8 @@ static inline int cpu_mmu_index (CPUPPCState *env, bool ifetch) /* Compatibility modes */ #if defined(TARGET_PPC64) +bool ppc_check_compat(PowerPCCPU *cpu, uint32_t compat_pvr, + uint32_t min_compat_pvr, uint32_t max_compat_pvr); void ppc_set_compat(PowerPCCPU *cpu, uint32_t compat_pvr, Error **errp); int ppc_compat_max_threads(PowerPCCPU *cpu); #endif /* defined(TARGET_PPC64) */ -- cgit v1.2.3