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Message-ID: <6d38f5eeb1661f613bc020c4e71b3ea33e87afa1.camel@linux.ibm.com>
Subject: [V2 PATCH 07/16] powerpc/vas: Define QoS credit flag to allocate
 window
From:   Haren Myneni <haren@linux.ibm.com>
To:     linuxppc-dev@lists.ozlabs.org, linux-crypto@vger.kernel.org,
        mpe@ellerman.id.au, herbert@gondor.apana.org.au, npiggin@gmail.com
Cc:     hbabu@us.ibm.com
Date:   Tue, 13 Apr 2021 01:24:18 -0700
In-Reply-To: <68aa9f2860f9acffa41469d3858883c938634722.camel@linux.ibm.com>
References: <68aa9f2860f9acffa41469d3858883c938634722.camel@linux.ibm.com>
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pHyp 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, phyp
introduces QoS credit type which makes sure guaranteed access to NX
resources. The system admins can assign QoS credits for 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_WIN_QOS_CREDITS
flag with VAS_TX_WIN_OPEN ioctl to open VAS 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..eb7c8694174f 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 default credit is used */
+#define	VAS_WIN_QOS_CREDITS	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