8868022634
Security fixes. OBS-URL: https://build.opensuse.org/request/show/494734 OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=339
103 lines
3.9 KiB
Diff
103 lines
3.9 KiB
Diff
From 5cff035804d92d336b27c368754b63e2dccbba90 Mon Sep 17 00:00:00 2001
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From: Alexander Graf <agraf@suse.de>
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Date: Tue, 28 Mar 2017 05:27:00 -0600
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Subject: [PATCH] i386: Allow cpuid bit override
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KVM has a feature bitmap of CPUID bits that it knows works for guests.
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QEMU removes bits that are not part of that bitmap automatically on VM
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start.
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However, some times we just don't list features in that list because
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they don't make sense for normal scenarios, but may be useful in specific,
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targeted workloads.
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For that purpose, add a new =force option to all CPUID feature flags in
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the CPU property. With that we can override the accel filtering and give
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users full control over the CPUID feature bits exposed into guests.
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Signed-off-by: Alexander Graf <agraf@suse.de>
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---
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target/i386/cpu.c | 25 ++++++++++++++++++++++---
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target/i386/cpu.h | 3 +++
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2 files changed, 25 insertions(+), 3 deletions(-)
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diff --git a/target/i386/cpu.c b/target/i386/cpu.c
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index 13c0985f11..6105fc513e 100644
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--- a/target/i386/cpu.c
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+++ b/target/i386/cpu.c
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@@ -2229,7 +2229,7 @@ void x86_cpu_list(FILE *f, fprintf_function cpu_fprintf)
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g_slist_foreach(list, x86_cpu_list_entry, &s);
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g_slist_free(list);
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- (*cpu_fprintf)(f, "\nRecognized CPUID flags:\n");
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+ (*cpu_fprintf)(f, "\nRecognized CPUID flags (=on|=off|=force):\n");
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for (i = 0; i < ARRAY_SIZE(feature_word_info); i++) {
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FeatureWordInfo *fw = &feature_word_info[i];
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@@ -3464,6 +3464,7 @@ static int x86_cpu_filter_features(X86CPU *cpu)
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x86_cpu_get_supported_feature_word(w, false);
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uint32_t requested_features = env->features[w];
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env->features[w] &= host_feat;
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+ env->features[w] |= cpu->forced_features[w];
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cpu->filtered_features[w] = requested_features & ~env->features[w];
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if (cpu->filtered_features[w]) {
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rv = 1;
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@@ -3706,8 +3707,17 @@ static void x86_cpu_get_bit_prop(Object *obj, Visitor *v, const char *name,
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X86CPU *cpu = X86_CPU(obj);
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BitProperty *fp = opaque;
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uint32_t f = cpu->env.features[fp->w];
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+ uint32_t ff = cpu->forced_features[fp->w];
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bool value = (f & fp->mask) == fp->mask;
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- visit_type_bool(v, name, &value, errp);
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+ bool forced = (ff & fp->mask) == fp->mask;
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+ char str[] = "force";
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+ char *strval = str;
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+
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+ if (forced) {
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+ visit_type_str(v, name, &strval, errp);
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+ } else {
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+ visit_type_bool(v, name, &value, errp);
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+ }
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}
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static void x86_cpu_set_bit_prop(Object *obj, Visitor *v, const char *name,
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@@ -3717,6 +3727,7 @@ static void x86_cpu_set_bit_prop(Object *obj, Visitor *v, const char *name,
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X86CPU *cpu = X86_CPU(obj);
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BitProperty *fp = opaque;
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Error *local_err = NULL;
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+ char *strval = NULL;
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bool value;
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if (dev->realized) {
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@@ -3724,7 +3735,15 @@ static void x86_cpu_set_bit_prop(Object *obj, Visitor *v, const char *name,
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return;
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}
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- visit_type_bool(v, name, &value, &local_err);
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+ visit_type_str(v, name, &strval, &local_err);
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+ if (!local_err && !strcmp(strval, "force")) {
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+ value = true;
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+ cpu->forced_features[fp->w] |= fp->mask;
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+ } else {
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+ local_err = NULL;
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+ visit_type_bool(v, name, &value, &local_err);
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+ }
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+
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if (local_err) {
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error_propagate(errp, local_err);
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return;
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diff --git a/target/i386/cpu.h b/target/i386/cpu.h
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index 81c02c5a3b..a458c3af9b 100644
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--- a/target/i386/cpu.h
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+++ b/target/i386/cpu.h
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@@ -1230,6 +1230,9 @@ struct X86CPU {
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/* Features that were filtered out because of missing host capabilities */
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uint32_t filtered_features[FEATURE_WORDS];
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+ /* Features that are force enabled despite incompatible accel */
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+ uint32_t forced_features[FEATURE_WORDS];
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+
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/* Enable PMU CPUID bits. This can't be enabled by default yet because
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* it doesn't have ABI stability guarantees, as it passes all PMU CPUID
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* bits returned by GET_SUPPORTED_CPUID (that depend on host CPU and kernel
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