From 2025fc6766ab25501e0041c564c44bb0f7389774 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 30 Mar 2020 13:52:28 +0100 Subject: [PATCH] hw/ppc/ppc440_uc.c: Remove incorrect iothread locking from dcr_write_pcie() In dcr_write_pcie() we take the iothread lock around a call to pcie_host_mmcfg_udpate(). This is an incorrect attempt to deal with the bug fixed in commit 235352ee6e73d7716, where we were not taking the iothread lock before calling device dcr read/write functions. (It's not sufficient locking, because although the other cases in the switch statement won't assert, there is no locking which prevents multiple guest CPUs from trying to access the PPC460EXPCIEState struct at the same time and corrupting data.) Unfortunately with commit 235352ee6e73d7716 we are now trying to recursively take the iothread lock, which will assert: $ qemu-system-ppc -M sam460ex --display none ** ERROR:/home/petmay01/linaro/qemu-from-laptop/qemu/cpus.c:1830:qemu_mutex_lock_iothread_impl: assertion failed: (!qemu_mutex_iothread_locked()) Aborted (core dumped) Remove the locking within dcr_write_pcie(). Fixes: 235352ee6e73d7716 Signed-off-by: Peter Maydell Message-Id: <20200330125228.24994-1-peter.maydell@linaro.org> Tested-by: BALATON Zoltan Signed-off-by: David Gibson --- hw/ppc/ppc440_uc.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/hw/ppc/ppc440_uc.c b/hw/ppc/ppc440_uc.c index d5ea962249..b30e093cbb 100644 --- a/hw/ppc/ppc440_uc.c +++ b/hw/ppc/ppc440_uc.c @@ -13,7 +13,6 @@ #include "qemu/error-report.h" #include "qapi/error.h" #include "qemu/log.h" -#include "qemu/main-loop.h" #include "qemu/module.h" #include "cpu.h" #include "hw/irq.h" @@ -1183,9 +1182,7 @@ static void dcr_write_pcie(void *opaque, int dcrn, uint32_t val) case PEGPL_CFGMSK: s->cfg_mask = val; size = ~(val & 0xfffffffe) + 1; - qemu_mutex_lock_iothread(); pcie_host_mmcfg_update(PCIE_HOST_BRIDGE(s), val & 1, s->cfg_base, size); - qemu_mutex_unlock_iothread(); break; case PEGPL_MSGBAH: s->msg_base = ((uint64_t)val << 32) | (s->msg_base & 0xffffffff);