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Re: [Qemu-devel] [PATCH v3] xilinx_spips: Correct usage of an uninitiali
From: |
francisco iglesias |
Subject: |
Re: [Qemu-devel] [PATCH v3] xilinx_spips: Correct usage of an uninitialized local variable |
Date: |
Thu, 25 Jan 2018 15:24:49 +0100 |
On Thursday, 25 January 2018, Peter Maydell <address@hidden>
wrote:
> On 24 January 2018 at 21:57, Francisco Iglesias
> <address@hidden> wrote:
> > Coverity found that the variable tx_rx in the function
> > xilinx_spips_flush_txfifo was being used uninitialized (CID 1383841).
> This
> > patch corrects this by always initializing tx_rx to zeros.
> >
> > Signed-off-by: Francisco Iglesias <address@hidden>
> >
> > ---
> > v3. Change to report errors on the num_busses property via the Error**
> > parameter when realizing the devices.
> > ---
> > v2. Add a sanity check on the num_busses property when realizing the
> > devices.
> > ---
> > hw/ssi/xilinx_spips.c | 18 +++++++++++++++++-
> > 1 file changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c
> > index 85c5d0c..8af36ca 100644
> > --- a/hw/ssi/xilinx_spips.c
> > +++ b/hw/ssi/xilinx_spips.c
> > @@ -210,6 +210,9 @@
> > #define SNOOP_NONE 0xEE
> > #define SNOOP_STRIPING 0
> >
> > +#define MIN_NUM_BUSSES 1
> > +#define MAX_NUM_BUSSES 2
> > +
> > static inline int num_effective_busses(XilinxSPIPS *s)
> > {
> > return (s->regs[R_LQSPI_CFG] & LQSPI_CFG_SEP_BUS &&
> > @@ -573,7 +576,7 @@ static void xilinx_spips_flush_txfifo(XilinxSPIPS
> *s)
> > for (;;) {
> > int i;
> > uint8_t tx = 0;
> > - uint8_t tx_rx[num_effective_busses(s)];
> > + uint8_t tx_rx[MAX_NUM_BUSSES] = { 0 };
> > uint8_t dummy_cycles = 0;
> > uint8_t addr_length;
> >
> > @@ -1221,6 +1224,19 @@ static void xilinx_spips_realize(DeviceState
> *dev, Error **errp)
> >
> > DB_PRINT_L(0, "realized spips\n");
> >
> > + if (s->num_busses > MAX_NUM_BUSSES) {
> > + error_setg(errp,
> > + "requested number of SPI busses %u exceeds maximum
> %d",
> > + s->num_busses, MAX_NUM_BUSSES);
> > + return;
> > + }
> > + if (s->num_busses < MIN_NUM_BUSSES) {
> > + error_setg(errp,
> > + "requested number of SPI busses %u is below minimum
> %d",
> > + s->num_busses, MIN_NUM_BUSSES);
> > + return;
> > + }
> > +
>
> The usual plural of "bus" is "buses", but since it's in the QOM
> property name I guess we're stuck with "busses" here for consistency...
>
>
> Applied to target-arm.next, thanks.
>
> -- PMM
>
Hi Peter,
Thank you very much again for looking into this!
Best regards,
Francisco Iglesias