[PATCH V2] Doc: admin-guide: Add entry for kvm_cma_resv_ratio kernel param

[sathnaga at linux.vnet.ibm.com]

From: Satheesh Rajendran <sathnaga at linux.vnet.ibm.com>

Add document entry for kvm_cma_resv_ratio kernel param which
is used to alter the KVM contiguous memory allocation percentage
for hash pagetable allocation used by hash mode PowerPC KVM guests.

Cc: linux-kernel at vger.kernel.org
Cc: kvm-ppc at vger.kernel.org
Cc: linuxppc-dev at lists.ozlabs.org
Cc: Paul Mackerras <paulus at samba.org>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Jonathan Corbet <corbet at lwn.net>
Reviewed-by: Randy Dunlap <rdunlap at infradead.org>
Signed-off-by: Satheesh Rajendran <sathnaga at linux.vnet.ibm.com>
---

V2: 
Addressed review comments from Randy.

V1: https://lkml.org/lkml/2020/9/16/72
---
 Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a1068742a6df..932ed45740c9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2258,6 +2258,14 @@
 			[KVM,ARM] Allow use of GICv4 for direct injection of
 			LPIs.
 
+	kvm_cma_resv_ratio=n [PPC]
+			Reserves given percentage from system memory area for
+			contiguous memory allocation for KVM hash pagetable
+			allocation.
+			By default it reserves 5% of total system memory.
+			Format: <integer>
+			Default: 5
+
 	kvm-intel.ept=	[KVM,Intel] Disable extended page tables
 			(virtualized MMU) support on capable Intel chips.
 			Default is 1 (enabled)
-- 
2.26.2