Re: [Qemu-devel] [Qemu devel V4 PATCH] msf2: Remove dead code reported by Coverity

[Darren Kenny]

LGTM now, thanks.

Reviewed-by: Darren Kenny <darren.ke...@oracle.com>

Thanks,

Darren.

On Wed, Oct 25, 2017 at 07:59:04AM +0530, Subbaraya Sundeep wrote:

Fixed incorrect frame size mask, validated maximum frame
size in spi_write and removed dead code.

Signed-off-by: Subbaraya Sundeep <sundeep.l...@gmail.com>
---
v4:
        changed %d to %u while logging frame size error.
v3:
        Added comment that [31:6] bits are reserved in R_SPI_DFSIZE
        register and logged incorrect value too in guest error(suggested
        by Darren).
v2:
        else if -> else in set_fifodepth
        log guest error when frame size is more than 32

hw/ssi/mss-spi.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/hw/ssi/mss-spi.c b/hw/ssi/mss-spi.c
index 5a8e308..d60daba 100644
--- a/hw/ssi/mss-spi.c
+++ b/hw/ssi/mss-spi.c
@@ -76,9 +76,10 @@
#define C_BIGFIFO            (1 << 29)
#define C_RESET              (1 << 31)

-#define FRAMESZ_MASK         0x1F
+#define FRAMESZ_MASK         0x3F
#define FMCOUNT_MASK         0x00FFFF00
#define FMCOUNT_SHIFT        8
+#define FRAMESZ_MAX          32

static void txfifo_reset(MSSSpiState *s)
{
@@ -104,10 +105,8 @@ static void set_fifodepth(MSSSpiState *s)
        s->fifo_depth = 32;
    } else if (size <= 16) {
        s->fifo_depth = 16;
-    } else if (size <= 32) {
-        s->fifo_depth = 8;
    } else {
-        s->fifo_depth = 4;
+        s->fifo_depth = 8;
    }
}

@@ -301,6 +300,17 @@ static void spi_write(void *opaque, hwaddr addr,
        if (s->enabled) {
            break;
        }
+        /*
+         * [31:6] bits are reserved bits and for future use.
+         * [5:0] are for frame size. Only [5:0] bits are validated
+         * during write, [31:6] bits are untouched.
+         */
+        if ((value & FRAMESZ_MASK) > FRAMESZ_MAX) {
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: Incorrect size %u provided."
+                         "Maximum frame size is %u\n",
+                         __func__, value & FRAMESZ_MASK, FRAMESZ_MAX);
+            break;
+        }
        s->regs[R_SPI_DFSIZE] = value;
        break;

--
2.5.0