[PATCH v5 09/17] powerpc/vas: Define QoS credit flag to allocate window

Haren Myneni
2021-06-13T11:00:41Z

PowerVM introduces two different type of credits: Default and Quality
of service (QoS).

The total number of default credits available on each LPAR depends
on CPU resources configured. But these credits can be shared or
over-committed across LPARs in shared mode which can result in
paste command failure (RMA_busy). To avoid NX HW contention, the
hypervisor ntroduces QoS credit type which makes sure guaranteed
access to NX esources. The system admins can assign QoS credits
or each LPAR via HMC.

Default credit type is used to allocate a VAS window by default as
on PowerVM implementation. But the process can pass
VAS_TX_WIN_FLAG_QOS_CREDIT flag with VAS_TX_WIN_OPEN ioctl to open
QoS type window.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
arch/powerpc/include/uapi/asm/vas-api.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/uapi/asm/vas-api.h b/arch/powerpc/include/uapi/asm/vas-api.h
index ebd4b2424785..7c81301ecdba 100644
--- a/arch/powerpc/include/uapi/asm/vas-api.h
+++ b/arch/powerpc/include/uapi/asm/vas-api.h
@@ -13,11 +13,15 @@
#define VAS_MAGIC 'v'
#define VAS_TX_WIN_OPEN _IOW(VAS_MAGIC, 0x20, struct vas_tx_win_open_attr)

+/* Flags to VAS TX open window ioctl */
+/* To allocate a window with QoS credit, otherwise use default credit */
+#define VAS_TX_WIN_FLAG_QOS_CREDIT 0x0000000000000001
+
struct vas_tx_win_open_attr {
__u32 version;
__s16 vas_id; /* specific instance of vas or -1 for default */
__u16 reserved1;
- __u64 flags; /* Future use */
+ __u64 flags;
__u64 reserved2[6];
};

--
2.18.2