diff options
author | Aditya Gupta <adityag@linux.ibm.com> | 2024-07-31 11:20:20 +0530 |
---|---|---|
committer | Nicholas Piggin <npiggin@gmail.com> | 2024-11-04 09:11:45 +1000 |
commit | ac0fbbb2d02bc68b3c0bbc873e40dc0d75e71f4d (patch) | |
tree | 17dff6674bc7730c79f0bb958ad42021e9c0ddbd | |
parent | c0b2f0dd6ba71cc4e31d92eb0f8571a4b37d3853 (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.c | 4 |
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; |