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target/arm: ignore evtstrm and cpuid CPU features

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evtstrm and cpuid cann't be controlled by VMM:
1. evtstrm: The generic timer is configured to generate events at a
   frequency of approximately 100KHz.  It's controlled by the linux
   kernel config CONFIG_ARM_ARCH_TIMER_EVTSTREAM.
2. cpuid: EL0 access to certain ID registers is available.  It's always
   set by linux kernel after 77c97b4ee2129 ("arm64: cpufeature: Expose
   CPUID registers by emulation").
However, they are exposed by getauxval() and /proc/cpuinfo.  Hence,
let's report and ignore the CPU features if someone set them.

Signed-off-by: Peng Liang <liangpeng10@huawei.com>
Signed-off-by: Dongxu Sun <sundongxu3@huawei.com>
This commit is contained in:
Chen Qun 2020-09-07 14:07:07 +08:00 committed by yezengruan
parent a8d152c93d
commit 37e14d976a
1 changed files with 67 additions and 0 deletions
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67
target-arm-ignore-evtstrm-and-cpuid-CPU-features.patch Normal file
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@ -0,0 +1,67 @@
From 4558dc5590b89b1252baea2734c2b3668566e5cb Mon Sep 17 00:00:00 2001
From: Peng Liang <liangpeng10@huawei.com>
Date: Mon, 7 Sep 2020 14:07:07 +0800
Subject: [PATCH] target/arm: ignore evtstrm and cpuid CPU features
evtstrm and cpuid cann't be controlled by VMM:
1. evtstrm: The generic timer is configured to generate events at a
frequency of approximately 100KHz. It's controlled by the linux
kernel config CONFIG_ARM_ARCH_TIMER_EVTSTREAM.
2. cpuid: EL0 access to certain ID registers is available. It's always
set by linux kernel after 77c97b4ee2129 ("arm64: cpufeature: Expose
CPUID registers by emulation").
However, they are exposed by getauxval() and /proc/cpuinfo. Hence,
let's report and ignore the CPU features if someone set them.
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
Signed-off-by: Dongxu Sun <sundongxu3@huawei.com>
---
target/arm/cpu64.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 9e5179afbe..287e7ac91c 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -982,10 +982,37 @@ static gchar *aarch64_gdb_arch_name(CPUState *cs)
return g_strdup("aarch64");
}
+static const char *unconfigurable_feats[] = {
+ "evtstrm",
+ "cpuid",
+ NULL
+};
+
+static bool is_configurable_feat(const char *name)
+{
+ int i;
+
+ for (i = 0; unconfigurable_feats[i]; ++i) {
+ if (g_strcmp0(unconfigurable_feats[i], name) == 0) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
static void
cpu_add_feat_as_prop(const char *typename, const char *name, const char *val)
{
- GlobalProperty *prop = g_new0(typeof(*prop), 1);
+ GlobalProperty *prop;
+
+ if (!is_configurable_feat(name)) {
+ info_report("CPU feature '%s' is not configurable by QEMU. Ignore it.",
+ name);
+ return;
+ }
+
+ prop = g_new0(typeof(*prop), 1);
prop->driver = typename;
prop->property = g_strdup(name);
prop->value = g_strdup(val);
--
2.27.0