[PATCH 5.10 029/142] s390: uv: Fix sysfs max number of VCPUs reporting

Greg Kroah-Hartman
2021-02-02T13:51:52Z

From: Janosch Frank <frankja@linux.ibm.com>

commit e82080e1f456467cc185fe65ee69fe9f9bd0b576 upstream.

The number reported by the query is N-1 and I think people reading the
sysfs file would expect N instead. For users creating VMs there's no
actual difference because KVM's limit is currently below the UV's
limit.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Fixes: a0f60f8431999 ("s390/protvirt: Add sysfs firmware interface for Ultravisor information")
Cc: stable@vger.kernel.org
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/s390/boot/uv.c b/arch/s390/boot/uv.c
index a15c033f53ca..87641dd65ccf 100644
--- a/arch/s390/boot/uv.c
+++ b/arch/s390/boot/uv.c
@@ -35,7 +35,7 @@ void uv_query_info(void)
uv_info.guest_cpu_stor_len = uvcb.cpu_stor_len;
uv_info.max_sec_stor_addr = ALIGN(uvcb.max_guest_stor_addr, PAGE_SIZE);
uv_info.max_num_sec_conf = uvcb.max_num_sec_conf;
- uv_info.max_guest_cpus = uvcb.max_guest_cpus;
+ uv_info.max_guest_cpu_id = uvcb.max_guest_cpu_id;
}

#ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index 0325fc0469b7..7b98d4caee77 100644
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -96,7 +96,7 @@ struct uv_cb_qui {
u32 max_num_sec_conf;
u64 max_guest_stor_addr;
u8 reserved88[158 - 136];
- u16 max_guest_cpus;
+ u16 max_guest_cpu_id;
u8 reserveda0[200 - 160];
} __packed __aligned(8);

@@ -273,7 +273,7 @@ struct uv_info {
unsigned long guest_cpu_stor_len;
unsigned long max_sec_stor_addr;
unsigned int max_num_sec_conf;
- unsigned short max_guest_cpus;
+ unsigned short max_guest_cpu_id;
};

extern struct uv_info uv_info;
diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index 883bfed9f5c2..b2d2ad153067 100644
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -368,7 +368,7 @@ static ssize_t uv_query_max_guest_cpus(struct kobject *kobj,
struct kobj_attribute *attr, char *page)
{
return scnprintf(page, PAGE_SIZE, "%d\n",
- uv_info.max_guest_cpus);
+ uv_info.max_guest_cpu_id + 1);
}

static struct kobj_attribute uv_query_max_guest_cpus_attr =