Dexuan Cui <decui@xxxxxxxxxxxxx> writes:
> I got the hypercall error code on Hyper-V 2008 R2 when keeping running
> "rmmod hv_netvsc; modprobe hv_netvsc; rmmod hv_utils; modprobe hv_utils"
> in a Linux guest.
>
> Without the patch, the driver can occasionally fail to load.
>
> CC: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
> Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> ---
> arch/x86/include/uapi/asm/hyperv.h | 1 +
> drivers/hv/connection.c | 9 +++++++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
> index 90c458e..b9daffb 100644
> --- a/arch/x86/include/uapi/asm/hyperv.h
> +++ b/arch/x86/include/uapi/asm/hyperv.h
> @@ -225,6 +225,7 @@
> #define HV_STATUS_INVALID_HYPERCALL_CODE 2
> #define HV_STATUS_INVALID_HYPERCALL_INPUT 3
> #define HV_STATUS_INVALID_ALIGNMENT 4
> +#define HV_STATUS_INVALID_CONNECTION_ID 18
> #define HV_STATUS_INSUFFICIENT_BUFFERS 19
The gap beween 4 and 18 tells me there are other codes here ;-) Are they
all 'permanent failures'?
>
> typedef struct _HV_REFERENCE_TSC_PAGE {
> diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
> index c4acd1c..8bd05f3 100644
> --- a/drivers/hv/connection.c
> +++ b/drivers/hv/connection.c
> @@ -440,6 +440,15 @@ int vmbus_post_msg(void *buffer, size_t buflen)
> ret = hv_post_message(conn_id, 1, buffer, buflen);
>
> switch (ret) {
> + case HV_STATUS_INVALID_CONNECTION_ID:
> + /*
> + * We could get this if we send messages too
> + * frequently or the host is under low resource
> + * conditions: let's wait 1 more second before
> + * retrying the hypercall.
> + */
> + msleep(1000);
> + break;
In case it is our last try (No. 10) we will return '18' from the
function. I suggest we set ret = -ENOMEM here as well.
> case HV_STATUS_INSUFFICIENT_BUFFERS:
> ret = -ENOMEM;
Or should we treat these two equally? There is a smaller (100ms) sleep
between tries already, we can consider changing it instead.
> case -ENOMEM:
--
Vitaly
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