[PATCH] cuda: fix reset-all and power-off words

[Mark Cave-Ayland]

There is a long-standing bug in the CUDA implementation of the reset-all and
power-off words whereby an extra byte is written after the CUDA_RESET_SYSTEM
and CUDA_POWERDOWN commands.

This extra byte used to be ignored in QEMU until commits 017da0b568 ("cuda:
port POWERDOWN command to new framework") and 54e894442e ("cuda: port
RESET_SYSTEM command to new framework") added a check which rejects the
command if the command length is incorrect.

Fix the outgoing command length to remove the extra byte which allows the
reset-all and power-off words to work in QEMU once again.

Signed-off-by: Mark Cave-Ayland 
Fixes: https://gitlab.com/qemu-project/qemu/-/issues/624
---
 drivers/cuda.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cuda.c b/drivers/cuda.c
index 56d73e1..c89b174 100644
--- a/drivers/cuda.c
+++ b/drivers/cuda.c
@@ -177,7 +177,7 @@ static cuda_t *main_cuda;
 static void
 ppc32_reset_all(void)
 {
-        uint8_t cmdbuf[2], obuf[64];
+        uint8_t cmdbuf[1], obuf[64];

cmdbuf[0] = CUDA_RESET_SYSTEM;
         cuda_request(main_cuda, CUDA_PACKET, cmdbuf, sizeof(cmdbuf), obuf);
@@ -186,7 +186,7 @@ ppc32_reset_all(void)
 static void
 ppc32_poweroff(void)
 {
-        uint8_t cmdbuf[2], obuf[64];
+        uint8_t cmdbuf[1], obuf[64];

cmdbuf[0] = CUDA_POWERDOWN;
         cuda_request(main_cuda, CUDA_PACKET, cmdbuf, sizeof(cmdbuf), obuf);

[Hervé Poussineau]

Le 19/09/2021 à 12:25, Mark Cave-Ayland a écrit :
> There is a long-standing bug in the CUDA implementation of the reset-all and
> power-off words whereby an extra byte is written after the CUDA_RESET_SYSTEM
> and CUDA_POWERDOWN commands.
>
> This extra byte used to be ignored in QEMU until commits 017da0b568 ("cuda:
> port POWERDOWN command to new framework") and 54e894442e ("cuda: port
> RESET_SYSTEM command to new framework") added a check which rejects the
> command if the command length is incorrect.
>
> Fix the outgoing command length to remove the extra byte which allows the
> reset-all and power-off words to work in QEMU once again.
>
> Signed-off-by: Mark Cave-Ayland 
> Fixes: https://gitlab.com/qemu-project/qemu/-/issues/624
>
> drivers/cuda.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Hervé Poussineau

[Mark Cave-Ayland]

On 19/09/2021 11:25, Mark Cave-Ayland wrote:
> There is a long-standing bug in the CUDA implementation of the reset-all and
> power-off words whereby an extra byte is written after the CUDA_RESET_SYSTEM
> and CUDA_POWERDOWN commands.
>
> This extra byte used to be ignored in QEMU until commits 017da0b568 ("cuda:
> port POWERDOWN command to new framework") and 54e894442e ("cuda: port
> RESET_SYSTEM command to new framework") added a check which rejects the
> command if the command length is incorrect.
>
> Fix the outgoing command length to remove the extra byte which allows the
> reset-all and power-off words to work in QEMU once again.
>
> Signed-off-by: Mark Cave-Ayland 
> Fixes: https://gitlab.com/qemu-project/qemu/-/issues/624
>
> drivers/cuda.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cuda.c b/drivers/cuda.c
> index 56d73e1..c89b174 100644
> --- a/drivers/cuda.c
> +++ b/drivers/cuda.c
> @@ -177,7 +177,7 @@ static cuda_t *main_cuda;
>   static void
>   ppc32_reset_all(void)
>   {
>    uint8_t cmdbuf[2], obuf[64];
>    uint8_t cmdbuf[1], obuf[64];
>
>     cmdbuf[0] = CUDA_RESET_SYSTEM;
>     cuda_request(main_cuda, CUDA_PACKET, cmdbuf, sizeof(cmdbuf), obuf);
>
> @@ -186,7 +186,7 @@ ppc32_reset_all(void)
>   static void
>   ppc32_poweroff(void)
>   {
>    uint8_t cmdbuf[2], obuf[64];
>    uint8_t cmdbuf[1], obuf[64];
>
>     cmdbuf[0] = CUDA_POWERDOWN;
>     cuda_request(main_cuda, CUDA_PACKET, cmdbuf, sizeof(cmdbuf), obuf);

Applied to master.

ATB,

Mark.