* [PATCH for-5.0] hw/ppc: Take QEMU lock when calling ppc_dcr_read/write()
@ 2020-03-22 19:22 Peter Maydell
2020-03-23 2:33 ` David Gibson
0 siblings, 1 reply; 2+ messages in thread
From: Peter Maydell @ 2020-03-22 19:22 UTC (permalink / raw)
To: qemu-devel; +Cc: Amit Lazar, qemu-ppc, David Gibson
The ppc_dcr_read() and ppc_dcr_write() functions call into callbacks
in device code, so we need to hold the QEMU iothread lock while
calling them. This is the case already for the callsites in
kvmppc_handle_dcr_read/write(), but we must also take the lock when
calling the helpers from TCG.
This fixes a bug where attempting to initialise the PPC405EP
SDRAM will cause an assertion when sdram_map_bcr() attempts
to remap memory regions.
Reported-by: Amit Lazar <abasarlaz@hotmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Amit reported this bug via IRC.
target/ppc/timebase_helper.c | 40 +++++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 14 deletions(-)
diff --git a/target/ppc/timebase_helper.c b/target/ppc/timebase_helper.c
index 703bd9ed18b..d16360ab667 100644
--- a/target/ppc/timebase_helper.c
+++ b/target/ppc/timebase_helper.c
@@ -21,6 +21,7 @@
#include "exec/helper-proto.h"
#include "exec/exec-all.h"
#include "qemu/log.h"
+#include "qemu/main-loop.h"
/*****************************************************************************/
/* SPR accesses */
@@ -167,13 +168,19 @@ target_ulong helper_load_dcr(CPUPPCState *env, target_ulong dcrn)
raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
POWERPC_EXCP_INVAL |
POWERPC_EXCP_INVAL_INVAL, GETPC());
- } else if (unlikely(ppc_dcr_read(env->dcr_env,
- (uint32_t)dcrn, &val) != 0)) {
- qemu_log_mask(LOG_GUEST_ERROR, "DCR read error %d %03x\n",
- (uint32_t)dcrn, (uint32_t)dcrn);
- raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
- POWERPC_EXCP_INVAL |
- POWERPC_EXCP_PRIV_REG, GETPC());
+ } else {
+ int ret;
+
+ qemu_mutex_lock_iothread();
+ ret = ppc_dcr_read(env->dcr_env, (uint32_t)dcrn, &val);
+ qemu_mutex_unlock_iothread();
+ if (unlikely(ret != 0)) {
+ qemu_log_mask(LOG_GUEST_ERROR, "DCR read error %d %03x\n",
+ (uint32_t)dcrn, (uint32_t)dcrn);
+ raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
+ POWERPC_EXCP_INVAL |
+ POWERPC_EXCP_PRIV_REG, GETPC());
+ }
}
return val;
}
@@ -185,12 +192,17 @@ void helper_store_dcr(CPUPPCState *env, target_ulong dcrn, target_ulong val)
raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
POWERPC_EXCP_INVAL |
POWERPC_EXCP_INVAL_INVAL, GETPC());
- } else if (unlikely(ppc_dcr_write(env->dcr_env, (uint32_t)dcrn,
- (uint32_t)val) != 0)) {
- qemu_log_mask(LOG_GUEST_ERROR, "DCR write error %d %03x\n",
- (uint32_t)dcrn, (uint32_t)dcrn);
- raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
- POWERPC_EXCP_INVAL |
- POWERPC_EXCP_PRIV_REG, GETPC());
+ } else {
+ int ret;
+ qemu_mutex_lock_iothread();
+ ret = ppc_dcr_write(env->dcr_env, (uint32_t)dcrn, (uint32_t)val);
+ qemu_mutex_unlock_iothread();
+ if (unlikely(ret != 0)) {
+ qemu_log_mask(LOG_GUEST_ERROR, "DCR write error %d %03x\n",
+ (uint32_t)dcrn, (uint32_t)dcrn);
+ raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
+ POWERPC_EXCP_INVAL |
+ POWERPC_EXCP_PRIV_REG, GETPC());
+ }
}
}
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH for-5.0] hw/ppc: Take QEMU lock when calling ppc_dcr_read/write()
2020-03-22 19:22 [PATCH for-5.0] hw/ppc: Take QEMU lock when calling ppc_dcr_read/write() Peter Maydell
@ 2020-03-23 2:33 ` David Gibson
0 siblings, 0 replies; 2+ messages in thread
From: David Gibson @ 2020-03-23 2:33 UTC (permalink / raw)
To: Peter Maydell; +Cc: Amit Lazar, qemu-ppc, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 4187 bytes --]
On Sun, Mar 22, 2020 at 07:22:58PM +0000, Peter Maydell wrote:
> The ppc_dcr_read() and ppc_dcr_write() functions call into callbacks
> in device code, so we need to hold the QEMU iothread lock while
> calling them. This is the case already for the callsites in
> kvmppc_handle_dcr_read/write(), but we must also take the lock when
> calling the helpers from TCG.
>
> This fixes a bug where attempting to initialise the PPC405EP
> SDRAM will cause an assertion when sdram_map_bcr() attempts
> to remap memory regions.
>
> Reported-by: Amit Lazar <abasarlaz@hotmail.com>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Applied to ppc-for-5.0.
> ---
> Amit reported this bug via IRC.
>
> target/ppc/timebase_helper.c | 40 +++++++++++++++++++++++-------------
> 1 file changed, 26 insertions(+), 14 deletions(-)
>
> diff --git a/target/ppc/timebase_helper.c b/target/ppc/timebase_helper.c
> index 703bd9ed18b..d16360ab667 100644
> --- a/target/ppc/timebase_helper.c
> +++ b/target/ppc/timebase_helper.c
> @@ -21,6 +21,7 @@
> #include "exec/helper-proto.h"
> #include "exec/exec-all.h"
> #include "qemu/log.h"
> +#include "qemu/main-loop.h"
>
> /*****************************************************************************/
> /* SPR accesses */
> @@ -167,13 +168,19 @@ target_ulong helper_load_dcr(CPUPPCState *env, target_ulong dcrn)
> raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
> POWERPC_EXCP_INVAL |
> POWERPC_EXCP_INVAL_INVAL, GETPC());
> - } else if (unlikely(ppc_dcr_read(env->dcr_env,
> - (uint32_t)dcrn, &val) != 0)) {
> - qemu_log_mask(LOG_GUEST_ERROR, "DCR read error %d %03x\n",
> - (uint32_t)dcrn, (uint32_t)dcrn);
> - raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
> - POWERPC_EXCP_INVAL |
> - POWERPC_EXCP_PRIV_REG, GETPC());
> + } else {
> + int ret;
> +
> + qemu_mutex_lock_iothread();
> + ret = ppc_dcr_read(env->dcr_env, (uint32_t)dcrn, &val);
> + qemu_mutex_unlock_iothread();
> + if (unlikely(ret != 0)) {
> + qemu_log_mask(LOG_GUEST_ERROR, "DCR read error %d %03x\n",
> + (uint32_t)dcrn, (uint32_t)dcrn);
> + raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
> + POWERPC_EXCP_INVAL |
> + POWERPC_EXCP_PRIV_REG, GETPC());
> + }
> }
> return val;
> }
> @@ -185,12 +192,17 @@ void helper_store_dcr(CPUPPCState *env, target_ulong dcrn, target_ulong val)
> raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
> POWERPC_EXCP_INVAL |
> POWERPC_EXCP_INVAL_INVAL, GETPC());
> - } else if (unlikely(ppc_dcr_write(env->dcr_env, (uint32_t)dcrn,
> - (uint32_t)val) != 0)) {
> - qemu_log_mask(LOG_GUEST_ERROR, "DCR write error %d %03x\n",
> - (uint32_t)dcrn, (uint32_t)dcrn);
> - raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
> - POWERPC_EXCP_INVAL |
> - POWERPC_EXCP_PRIV_REG, GETPC());
> + } else {
> + int ret;
> + qemu_mutex_lock_iothread();
> + ret = ppc_dcr_write(env->dcr_env, (uint32_t)dcrn, (uint32_t)val);
> + qemu_mutex_unlock_iothread();
> + if (unlikely(ret != 0)) {
> + qemu_log_mask(LOG_GUEST_ERROR, "DCR write error %d %03x\n",
> + (uint32_t)dcrn, (uint32_t)dcrn);
> + raise_exception_err_ra(env, POWERPC_EXCP_PROGRAM,
> + POWERPC_EXCP_INVAL |
> + POWERPC_EXCP_PRIV_REG, GETPC());
> + }
> }
> }
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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