Re: [PATCH v3 3/5] hyperv: Enable the hypercall output page for the VTL mode

From: Easwar Hariharan
Date: Thu Dec 26 2024 - 16:42:41 EST


On 12/26/2024 1:31 PM, Roman Kisel wrote:
> Due to the hypercall page not being allocated in the VTL mode,
> the code resorts to using a part of the input page.
>
> Allocate the hypercall output page in the VTL mode thus enabling
> it to use it for output and share code with dom0.
>
> Signed-off-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/hv/hv_common.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index c4fd07d9bf1a..5178beed6ca8 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -340,7 +340,7 @@ int __init hv_common_init(void)
> BUG_ON(!hyperv_pcpu_input_arg);
>
> /* Allocate the per-CPU state for output arg for root */
> - if (hv_root_partition) {
> + if (hv_root_partition || IS_ENABLED(CONFIG_HYPERV_VTL_MODE)) {
> hyperv_pcpu_output_arg = alloc_percpu(void *);
> BUG_ON(!hyperv_pcpu_output_arg);
> }
> @@ -435,7 +435,7 @@ int hv_common_cpu_init(unsigned int cpu)
> void **inputarg, **outputarg;
> u64 msr_vp_index;
> gfp_t flags;
> - int pgcount = hv_root_partition ? 2 : 1;
> + const int pgcount = (hv_root_partition || IS_ENABLED(CONFIG_HYPERV_VTL_MODE)) ? 2 : 1;
> void *mem;
> int ret;

Thanks for the const!

Reviewed-by: Easwar Hariharan <eahariha@xxxxxxxxxxxxxxxxxxx>