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authorAditya Gupta <adityag@linux.ibm.com>2024-07-31 11:20:20 +0530
committerNicholas Piggin <npiggin@gmail.com>2024-11-04 09:11:45 +1000
commitac0fbbb2d02bc68b3c0bbc873e40dc0d75e71f4d (patch)
tree17dff6674bc7730c79f0bb958ad42021e9c0ddbd
parentc0b2f0dd6ba71cc4e31d92eb0f8571a4b37d3853 (diff)
target/ppc: Fix regression due to Power10 and Power11 having same PCR
Power11 has the same PCR (Processor Compatibility Register) value, as Power10. Due to this, QEMU considers Power11 as a valid compat-mode for Power10, ie. earlier it was possible to run QEMU with '-M pseries,max-compat-mode=power11 --cpu power10' Same PCR also introduced a regression where `-M pseries --cpu power10` boots as Power11 (ie. logical PVR is of Power11, even though PVR is Power10). The regression was due to 'do_client_architecture_support' checking for valid compat modes and finding Power11 to be a valid compat mode for Power10 (it happens even without passing 'max-compat-mode' explicitly). Fix compat-mode issue and regression, by ensuring a future Power processor (with a higher logical_pvr value, eg. P11) cannot be valid compat-mode for an older Power processor (eg. P10) Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Aditya Gupta <adityag@linux.ibm.com> Tested-by: Amit Machhiwal <amachhiw@linux.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
-rw-r--r--target/ppc/compat.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/target/ppc/compat.c b/target/ppc/compat.c
index ebef2cccec..5b20fd7ef0 100644
--- a/target/ppc/compat.c
+++ b/target/ppc/compat.c
@@ -132,6 +132,10 @@ static bool pcc_compat(PowerPCCPUClass *pcc, uint32_t compat_pvr,
/* Outside specified range */
return false;
}
+ if (compat->pvr > pcc->spapr_logical_pvr) {
+ /* Older CPU cannot support a newer processor's compat mode */
+ return false;
+ }
if (!(pcc->pcr_supported & compat->pcr_level)) {
/* Not supported by this CPU */
return false;