commit 8ff43ee404d3e295839d1fd4e9e6571ca7a62a66
author Suraj Jitindar Singh <sjitindarsingh@gmail.com> Fri Mar 01 14:19:12 2019 +1100
committer David Gibson <david@gibson.dropbear.id.au> Tue Mar 12 12:07:49 2019 +1100
tree f3a77de59523fe38cc5479afdc3087e8c7f7b53f
parent 399b2896d4948a1ec0278d896ea3a561df768d64

target/ppc/spapr: Add SPAPR_CAP_CCF_ASSIST

Introduce a new spapr_cap SPAPR_CAP_CCF_ASSIST to be used to indicate
the requirement for a hw-assisted version of the count cache flush
workaround.

The count cache flush workaround is a software workaround which can be
used to flush the count cache on context switch. Some revisions of
hardware may have a hardware accelerated flush, in which case the
software flush can be shortened. This cap is used to set the
availability of such hardware acceleration for the count cache flush
routine.

The availability of such hardware acceleration is indicated by the
H_CPU_CHAR_BCCTR_FLUSH_ASSIST flag being set in the characteristics
returned from the KVM_PPC_GET_CPU_CHAR ioctl.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Message-Id: <20190301031912.28809-2-sjitindarsingh@gmail.com>
[dwg: Small style fixes]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

target/ppc/kvm.c

diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 4d46314..1da2803 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -90,6 +90,7 @@
 static int cap_ppc_safe_cache;
 static int cap_ppc_safe_bounds_check;
 static int cap_ppc_safe_indirect_branch;
+static int cap_ppc_count_cache_flush_assist;
 static int cap_ppc_nested_kvm_hv;
 static int cap_large_decr;
 
@@ -2407,6 +2408,14 @@
     return 0;
 }
 
+static int parse_cap_ppc_count_cache_flush_assist(struct kvm_ppc_cpu_char c)
+{
+    if (c.character & c.character_mask & H_CPU_CHAR_BCCTR_FLUSH_ASSIST) {
+        return 1;
+    }
+    return 0;
+}
+
 static void kvmppc_get_cpu_characteristics(KVMState *s)
 {
     struct kvm_ppc_cpu_char c;
@@ -2429,6 +2438,8 @@
     cap_ppc_safe_cache = parse_cap_ppc_safe_cache(c);
     cap_ppc_safe_bounds_check = parse_cap_ppc_safe_bounds_check(c);
     cap_ppc_safe_indirect_branch = parse_cap_ppc_safe_indirect_branch(c);
+    cap_ppc_count_cache_flush_assist =
+        parse_cap_ppc_count_cache_flush_assist(c);
 }
 
 int kvmppc_get_cap_safe_cache(void)
@@ -2446,6 +2457,11 @@
     return cap_ppc_safe_indirect_branch;
 }
 
+int kvmppc_get_cap_count_cache_flush_assist(void)
+{
+    return cap_ppc_count_cache_flush_assist;
+}
+
 bool kvmppc_has_cap_nested_kvm_hv(void)
 {
     return !!cap_ppc_nested_kvm_hv;