This commit modifies the dwc2_hsotg_read() and dwc2_hsotg_write() functions
to handle invalid address access gracefully. Instead of using
g_assert_not_reached(), which causes the program to abort, the functions
now log an error message and return a default value for reads or do
nothing for writes.
This change prevents the program from aborting and provides clear log
messages indicating when an invalid memory address is accessed.
Reproducer:
cat << EOF | qemu-system-aarch64 -display none \
-machine accel=qtest, -m 512M -machine raspi2b -m 1G -nodefaults \
-usb -drive file=null-co://,if=none,format=raw,id=disk0 -device \
usb-storage,port=1,drive=disk0 -qtest stdio
readl 0x3f980dfb
EOF
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
---
hw/usb/hcd-dwc2.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c
index 8cac9c0a06..b4f0652c7d 100644
--- a/hw/usb/hcd-dwc2.c
+++ b/hw/usb/hcd-dwc2.c
@@ -1128,7 +1128,10 @@ static uint64_t dwc2_hsotg_read(void *ptr, hwaddr addr, unsigned size)
val = dwc2_pcgreg_read(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, size);
break;
default:
- g_assert_not_reached();
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n",
+ __func__, addr);
+ val = 0;
+ break;
}
return val;
@@ -1160,7 +1163,9 @@ static void dwc2_hsotg_write(void *ptr, hwaddr addr, uint64_t val,
dwc2_pcgreg_write(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, val, size);
break;
default:
- g_assert_not_reached();
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n",
+ __func__, addr);
+ break;
}
}
--
2.34.1On Tue, Jun 18, 2024 at 6:56 AM Zheyu Ma <zheyuma97@gmail.com> wrote: > > This commit modifies the dwc2_hsotg_read() and dwc2_hsotg_write() functions > to handle invalid address access gracefully. Instead of using > g_assert_not_reached(), which causes the program to abort, the functions > now log an error message and return a default value for reads or do > nothing for writes. > > This change prevents the program from aborting and provides clear log > messages indicating when an invalid memory address is accessed. > > Reproducer: > cat << EOF | qemu-system-aarch64 -display none \ > -machine accel=qtest, -m 512M -machine raspi2b -m 1G -nodefaults \ > -usb -drive file=null-co://,if=none,format=raw,id=disk0 -device \ > usb-storage,port=1,drive=disk0 -qtest stdio > readl 0x3f980dfb > EOF > > Signed-off-by: Zheyu Ma <zheyuma97@gmail.com> > --- > hw/usb/hcd-dwc2.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c > index 8cac9c0a06..b4f0652c7d 100644 > --- a/hw/usb/hcd-dwc2.c > +++ b/hw/usb/hcd-dwc2.c > @@ -1128,7 +1128,10 @@ static uint64_t dwc2_hsotg_read(void *ptr, hwaddr addr, unsigned size) > val = dwc2_pcgreg_read(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, size); > break; > default: > - g_assert_not_reached(); > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n", > + __func__, addr); > + val = 0; > + break; > } > > return val; > @@ -1160,7 +1163,9 @@ static void dwc2_hsotg_write(void *ptr, hwaddr addr, uint64_t val, > dwc2_pcgreg_write(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, val, size); > break; > default: > - g_assert_not_reached(); > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n", > + __func__, addr); > + break; > } > } > > -- > 2.34.1 Looks good to me. Reviewed-by: Paul Zimmerman <pauldzim@gmail.com>
Hi Paul, On 18/6/24 20:58, Paul Zimmerman wrote: > On Tue, Jun 18, 2024 at 6:56 AM Zheyu Ma <zheyuma97@gmail.com > <mailto:zheyuma97@gmail.com>> wrote: > > > > This commit modifies the dwc2_hsotg_read() and dwc2_hsotg_write() > functions > > to handle invalid address access gracefully. Instead of using > > g_assert_not_reached(), which causes the program to abort, the functions > > now log an error message and return a default value for reads or do > > nothing for writes. > > > > This change prevents the program from aborting and provides clear log > > messages indicating when an invalid memory address is accessed. > > > > Reproducer: > > cat << EOF | qemu-system-aarch64 -display none \ > > -machine accel=qtest, -m 512M -machine raspi2b -m 1G -nodefaults \ > > -usb -drive file=null-co://,if=none,format=raw,id=disk0 -device \ > > usb-storage,port=1,drive=disk0 -qtest stdio > > readl 0x3f980dfb > > EOF > > > > Signed-off-by: Zheyu Ma <zheyuma97@gmail.com > <mailto:zheyuma97@gmail.com>> > > --- > > hw/usb/hcd-dwc2.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c > > index 8cac9c0a06..b4f0652c7d 100644 > > --- a/hw/usb/hcd-dwc2.c > > +++ b/hw/usb/hcd-dwc2.c > > @@ -1128,7 +1128,10 @@ static uint64_t dwc2_hsotg_read(void *ptr, > hwaddr addr, unsigned size) > > val = dwc2_pcgreg_read(ptr, addr, (addr - HSOTG_REG(0xe00)) > >> 2, size); > > break; > > default: > > - g_assert_not_reached(); > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset > 0x%"HWADDR_PRIx"\n", > > + __func__, addr); > > + val = 0; > > + break; > > } > > > > return val; > > @@ -1160,7 +1163,9 @@ static void dwc2_hsotg_write(void *ptr, hwaddr > addr, uint64_t val, > > dwc2_pcgreg_write(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, > val, size); > > break; > > default: > > - g_assert_not_reached(); > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset > 0x%"HWADDR_PRIx"\n", > > + __func__, addr); > > + break; > > } > > } > > > > -- > > 2.34.1 > > Looks good to me. > > Reviewed-by: Paul Zimmerman <pauldzim@gmail.com <mailto:pauldzim@gmail.com>> > Does that mean on real HW the access to unassigned registers are silently ignored as RAZ/WI like this patch? (I don't have access to the specs -- IIRC you don't neither, but you might have real HW to test). Thanks, Phil.
On Tue, Jun 18, 2024 at 1:37 PM Philippe Mathieu-Daudé <philmd@linaro.org> wrote: > Hi Paul, > > On 18/6/24 20:58, Paul Zimmerman wrote: > > On Tue, Jun 18, 2024 at 6:56 AM Zheyu Ma <zheyuma97@gmail.com > > <mailto:zheyuma97@gmail.com>> wrote: > > > > > > This commit modifies the dwc2_hsotg_read() and dwc2_hsotg_write() > > functions > > > to handle invalid address access gracefully. Instead of using > > > g_assert_not_reached(), which causes the program to abort, the > functions > > > now log an error message and return a default value for reads or do > > > nothing for writes. > > > > > > This change prevents the program from aborting and provides clear log > > > messages indicating when an invalid memory address is accessed. > > > > > > Reproducer: > > > cat << EOF | qemu-system-aarch64 -display none \ > > > -machine accel=qtest, -m 512M -machine raspi2b -m 1G -nodefaults \ > > > -usb -drive file=null-co://,if=none,format=raw,id=disk0 -device \ > > > usb-storage,port=1,drive=disk0 -qtest stdio > > > readl 0x3f980dfb > > > EOF > > > > > > Signed-off-by: Zheyu Ma <zheyuma97@gmail.com > > <mailto:zheyuma97@gmail.com>> > > > --- > > > hw/usb/hcd-dwc2.c | 9 +++++++-- > > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > > > diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c > > > index 8cac9c0a06..b4f0652c7d 100644 > > > --- a/hw/usb/hcd-dwc2.c > > > +++ b/hw/usb/hcd-dwc2.c > > > @@ -1128,7 +1128,10 @@ static uint64_t dwc2_hsotg_read(void *ptr, > hwaddr addr, unsigned size) > > > val = dwc2_pcgreg_read(ptr, addr, (addr - HSOTG_REG(0xe00)) > >> 2, size); > > > break; > > > default: > > > - g_assert_not_reached(); > > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset > 0x%"HWADDR_PRIx"\n", > > > + __func__, addr); > > > + val = 0; > > > + break; > > > } > > > > > > return val; > > > @@ -1160,7 +1163,9 @@ static void dwc2_hsotg_write(void *ptr, hwaddr > addr, uint64_t val, > > > dwc2_pcgreg_write(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, > val, size); > > > break; > > > default: > > > - g_assert_not_reached(); > > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset > 0x%"HWADDR_PRIx"\n", > > > + __func__, addr); > > > + break; > > > } > > > } > > > > > > -- > > > 2.34.1 > > > > Looks good to me. > > > > Reviewed-by: Paul Zimmerman <pauldzim@gmail.com <mailto: > pauldzim@gmail.com>> > > > > Does that mean on real HW the access to unassigned registers are > silently ignored as RAZ/WI like this patch? (I don't have access > to the specs -- IIRC you don't neither, but you might have real > HW to test). Hi Phil, I have an old raspi around somewhere I could probably dig up and test with, but I'm not familiar with qtest, so I don't know how I would reproduce the failure on real hw. Besides, isn't it always better to fail and log an error than just crash? Regards, Paul
On Tue, 18 Jun 2024 at 22:33, Paul Zimmerman <pauldzim@gmail.com> wrote: > > On Tue, Jun 18, 2024 at 1:37 PM Philippe Mathieu-Daudé <philmd@linaro.org> wrote: >> >> Hi Paul, >> >> On 18/6/24 20:58, Paul Zimmerman wrote: >> > On Tue, Jun 18, 2024 at 6:56 AM Zheyu Ma <zheyuma97@gmail.com >> > <mailto:zheyuma97@gmail.com>> wrote: >> > > >> > > This commit modifies the dwc2_hsotg_read() and dwc2_hsotg_write() >> > functions >> > > to handle invalid address access gracefully. Instead of using >> > > g_assert_not_reached(), which causes the program to abort, the functions >> > > now log an error message and return a default value for reads or do >> > > nothing for writes. >> > > >> > > This change prevents the program from aborting and provides clear log >> > > messages indicating when an invalid memory address is accessed. >> > > >> > > Reproducer: >> > > cat << EOF | qemu-system-aarch64 -display none \ >> > > -machine accel=qtest, -m 512M -machine raspi2b -m 1G -nodefaults \ >> > > -usb -drive file=null-co://,if=none,format=raw,id=disk0 -device \ >> > > usb-storage,port=1,drive=disk0 -qtest stdio >> > > readl 0x3f980dfb >> > > EOF >> > > >> > > Signed-off-by: Zheyu Ma <zheyuma97@gmail.com >> > <mailto:zheyuma97@gmail.com>> >> > > --- >> > > hw/usb/hcd-dwc2.c | 9 +++++++-- >> > > 1 file changed, 7 insertions(+), 2 deletions(-) >> > > >> > > diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c >> > > index 8cac9c0a06..b4f0652c7d 100644 >> > > --- a/hw/usb/hcd-dwc2.c >> > > +++ b/hw/usb/hcd-dwc2.c >> > > @@ -1128,7 +1128,10 @@ static uint64_t dwc2_hsotg_read(void *ptr, hwaddr addr, unsigned size) >> > > val = dwc2_pcgreg_read(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, size); >> > > break; >> > > default: >> > > - g_assert_not_reached(); >> > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n", >> > > + __func__, addr); >> > > + val = 0; >> > > + break; >> > > } >> > > >> > > return val; >> > > @@ -1160,7 +1163,9 @@ static void dwc2_hsotg_write(void *ptr, hwaddr addr, uint64_t val, >> > > dwc2_pcgreg_write(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, val, size); >> > > break; >> > > default: >> > > - g_assert_not_reached(); >> > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n", >> > > + __func__, addr); >> > > + break; >> > > } >> > > } >> > > >> > > -- >> > > 2.34.1 >> > >> > Looks good to me. >> > >> > Reviewed-by: Paul Zimmerman <pauldzim@gmail.com <mailto:pauldzim@gmail.com>> >> > >> >> Does that mean on real HW the access to unassigned registers are >> silently ignored as RAZ/WI like this patch? (I don't have access >> to the specs -- IIRC you don't neither, but you might have real >> HW to test). > I have an old raspi around somewhere I could probably dig up and > test with, but I'm not familiar with qtest, so I don't know how I > would reproduce the failure on real hw. > > Besides, isn't it always better to fail and log an error than just crash? Yes, assert is definitely the wrong thing here. RAZ/WI and log a guest-error is what we typically do for devices where the spec doesn't give a behaviour for accesses to register offsets that aren't documented as having registers. I've applied this to target-arm.next; thanks. -- PMM
Cc'ing Paul. On 18/6/24 15:56, Zheyu Ma wrote: > This commit modifies the dwc2_hsotg_read() and dwc2_hsotg_write() functions > to handle invalid address access gracefully. Instead of using > g_assert_not_reached(), which causes the program to abort, the functions > now log an error message and return a default value for reads or do > nothing for writes. > > This change prevents the program from aborting and provides clear log > messages indicating when an invalid memory address is accessed. > > Reproducer: > cat << EOF | qemu-system-aarch64 -display none \ > -machine accel=qtest, -m 512M -machine raspi2b -m 1G -nodefaults \ > -usb -drive file=null-co://,if=none,format=raw,id=disk0 -device \ > usb-storage,port=1,drive=disk0 -qtest stdio > readl 0x3f980dfb > EOF > > Signed-off-by: Zheyu Ma <zheyuma97@gmail.com> > --- > hw/usb/hcd-dwc2.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c > index 8cac9c0a06..b4f0652c7d 100644 > --- a/hw/usb/hcd-dwc2.c > +++ b/hw/usb/hcd-dwc2.c > @@ -1128,7 +1128,10 @@ static uint64_t dwc2_hsotg_read(void *ptr, hwaddr addr, unsigned size) > val = dwc2_pcgreg_read(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, size); > break; > default: > - g_assert_not_reached(); > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n", > + __func__, addr); > + val = 0; > + break; > } > > return val; > @@ -1160,7 +1163,9 @@ static void dwc2_hsotg_write(void *ptr, hwaddr addr, uint64_t val, > dwc2_pcgreg_write(ptr, addr, (addr - HSOTG_REG(0xe00)) >> 2, val, size); > break; > default: > - g_assert_not_reached(); > + qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n", > + __func__, addr); > + break; > } > } >
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