public-mirrors/linux
1
0
Fork 0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-08-05 16:54:27 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Drivers: hv: Introduce per-cpu event ring tail

Browse source 
Add a pointer hv_synic_eventring_tail to track the tail pointer for the
SynIC event ring buffer for each SINT.

This will be used by the mshv driver, but must be tracked independently
since the driver module could be removed and re-inserted.

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Link: https://lore.kernel.org/r/1741980536-3865-8-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1741980536-3865-8-git-send-email-nunodasneves@linux.microsoft.com>
This commit is contained in:
Nuno Das Neves 2025-03-14 12:28:53 -07:00 • committed by Wei Liu
parent 21050f6197
commit 04df7ac399
1 changed files with 37 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

41
drivers/hv/hv_common.c
View file

@ -68,6 +68,16 @@ static void hv_kmsg_dump_unregister(void);
static struct ctl_table_header *hv_ctl_table_hdr;
/*
* Per-cpu array holding the tail pointer for the SynIC event ring buffer
* for each SINT.
*
* We cannot maintain this in mshv driver because the tail pointer should
* persist even if the mshv driver is unloaded.
*/
u8 * __percpu *hv_synic_eventring_tail;
EXPORT_SYMBOL_GPL(hv_synic_eventring_tail);
/*
* Hyper-V specific initialization and shutdown code that is
* common across all architectures. Called from architecture
@ -90,6 +100,9 @@ void __init hv_common_free(void)
free_percpu(hyperv_pcpu_input_arg);
hyperv_pcpu_input_arg = NULL;
free_percpu(hv_synic_eventring_tail);
hv_synic_eventring_tail = NULL;
}
/*
@ -372,6 +385,11 @@ int __init hv_common_init(void)
BUG_ON(!hyperv_pcpu_output_arg);
}
if (hv_root_partition()) {
hv_synic_eventring_tail = alloc_percpu(u8 *);
BUG_ON(!hv_synic_eventring_tail);
}
hv_vp_index = kmalloc_array(nr_cpu_ids, sizeof(*hv_vp_index),
GFP_KERNEL);
if (!hv_vp_index) {
@ -460,11 +478,12 @@ error:
int hv_common_cpu_init(unsigned int cpu)
{
void **inputarg, **outputarg;
u8 **synic_eventring_tail;
u64 msr_vp_index;
gfp_t flags;
const int pgcount = hv_output_page_exists() ? 2 : 1;
void *mem;
int ret;
int ret = 0;
/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
@ -472,8 +491,8 @@ int hv_common_cpu_init(unsigned int cpu)
inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
/*
* hyperv_pcpu_input_arg and hyperv_pcpu_output_arg memory is already
* allocated if this CPU was previously online and then taken offline
* The per-cpu memory is already allocated if this CPU was previously
* online and then taken offline
*/
if (!*inputarg) {
mem = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags);
@ -520,11 +539,21 @@ int hv_common_cpu_init(unsigned int cpu)
if (msr_vp_index > hv_max_vp_index)
hv_max_vp_index = msr_vp_index;
return 0;
if (hv_root_partition()) {
synic_eventring_tail = (u8 **)this_cpu_ptr(hv_synic_eventring_tail);
*synic_eventring_tail = kcalloc(HV_SYNIC_SINT_COUNT,
sizeof(u8), flags);
/* No need to unwind any of the above on failure here */
if (unlikely(!*synic_eventring_tail))
ret = -ENOMEM;
}
return ret;
}
int hv_common_cpu_die(unsigned int cpu)
{
u8 **synic_eventring_tail;
/*
* The hyperv_pcpu_input_arg and hyperv_pcpu_output_arg memory
* is not freed when the CPU goes offline as the hyperv_pcpu_input_arg
@ -537,6 +566,10 @@ int hv_common_cpu_die(unsigned int cpu)
* originally allocated memory is reused in hv_common_cpu_init().
*/
synic_eventring_tail = this_cpu_ptr(hv_synic_eventring_tail);
kfree(*synic_eventring_tail);
*synic_eventring_tail = NULL;
return 0;
}