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From: | Cédric Le Goater |
Subject: | Re: [PATCH] pnv_lpc: disable reentrancy detection for lpc-hc |
Date: | Thu, 11 May 2023 11:36:58 +0200 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 |
On 5/11/23 11:15, Alexander Bulekov wrote:
On 230511 1104, Cédric Le Goater wrote:Hello Alexander On 5/11/23 10:53, Alexander Bulekov wrote:As lpc-hc is designed for re-entrant calls from xscom, mark it re-entrancy safe. Reported-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Alexander Bulekov <alxndr@bu.edu> --- hw/ppc/pnv_lpc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/ppc/pnv_lpc.c b/hw/ppc/pnv_lpc.c index 01f44c19eb..67fd049a7f 100644 --- a/hw/ppc/pnv_lpc.c +++ b/hw/ppc/pnv_lpc.c @@ -738,6 +738,8 @@ static void pnv_lpc_realize(DeviceState *dev, Error **errp) &lpc->opb_master_regs); memory_region_init_io(&lpc->lpc_hc_regs, OBJECT(dev), &lpc_hc_ops, lpc, "lpc-hc", LPC_HC_REGS_OPB_SIZE); + /* xscom writes to lpc-hc. As such mark lpc-hc re-entrancy safe */ + lpc->lpc_hc_regs.disable_reentrancy_guard = true; memory_region_add_subregion(&lpc->opb_mr, LPC_HC_REGS_OPB_ADDR, &lpc->lpc_hc_regs);The warning changed : qemu-system-ppc64: warning: Blocked re-entrant IO on MemoryRegion: lpc-opb-master at addr: 0x8 I will take a look unless you know exactly what to do.That does not show up for me with "./qemu-system-ppc64 -M powernv8" Do I need to boot a kernel to see the message?
There are other processors: powernv10 IBM PowerNV (Non-Virtualized) POWER10 powernv8 IBM PowerNV (Non-Virtualized) POWER8 powernv IBM PowerNV (Non-Virtualized) POWER9 (alias of powernv9) powernv9 IBM PowerNV (Non-Virtualized) POWER9 Region lpc->opb_master_regs needs to be tagged also for powernv9 and powernv10. Thanks, C.
I was worried that there might be other re-entrant IO in this device. Maybe there should be a way to just mark the whole device re-entrancy safe.
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