[pve-devel] [PATCH kvm] Added: target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID

[Wolfgang Bumiller]

Fixes a freezing problelm when migrating from older qemu.
---
 ...-do-not-read-write-MSR_TSC_AUX-from-KVM-i.patch | 38 ++++++++++++++++++++++
 debian/patches/series                              |  1 +
 2 files changed, 39 insertions(+)
 create mode 100644 debian/patches/extra/0001-target-i386-do-not-read-write-MSR_TSC_AUX-from-KVM-i.patch

diff --git a/debian/patches/extra/0001-target-i386-do-not-read-write-MSR_TSC_AUX-from-KVM-i.patch b/debian/patches/extra/0001-target-i386-do-not-read-write-MSR_TSC_AUX-from-KVM-i.patch
new file mode 100644
index 0000000..4077fa3
--- /dev/null
+++ b/debian/patches/extra/0001-target-i386-do-not-read-write-MSR_TSC_AUX-from-KVM-i.patch
@@ -0,0 +1,38 @@
+From 73a3187cc97cdc8c11f4781910307e5dde5e8dbc Mon Sep 17 00:00:00 2001
+From: Paolo Bonzini <pbonzini at redhat.com>
+Date: Wed, 30 Mar 2016 22:59:42 +0200
+Subject: [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID
+ bit is not set
+
+KVM does not let you read or write this MSR if the corresponding CPUID
+bit is not set.  This in turn causes MSRs that come after MSR_TSC_AUX
+to be ignored by KVM_SET_MRSS.
+
+One visible symptom is that s3.flat from kvm-unit-tests fails with
+CPUs that do not have RDTSCP, because the SMBASE is not reset to
+0x30000 after reset.
+
+Fixes: c9b8f6b6210847b4381c5b2ee172b1c7eb9985d6
+Cc: qemu-stable at nongnu.org
+Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
+---
+ target-i386/kvm.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/target-i386/kvm.c b/target-i386/kvm.c
+index 36fa3f0..7370e9e 100644
+--- a/target-i386/kvm.c
++++ b/target-i386/kvm.c
+@@ -846,6 +846,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
+     if (env->features[FEAT_1_EDX] & CPUID_MTRR) {
+         has_msr_mtrr = true;
+     }
++    if (!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) {
++        has_msr_tsc_aux = false;
++    }
+ 
+     return 0;
+ }
+-- 
+2.1.4
+
diff --git a/debian/patches/series b/debian/patches/series
index 3ff759d..e165c81 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -50,3 +50,4 @@ extra/0002-rng-move-request-queue-from-RngEgd-to-RngBackend.patch
 extra/0003-rng-move-request-queue-cleanup-from-RngEgd-to-RngBac.patch
 extra/CVE-2016-2858-0004-rng-add-request-queue-support-to-rng-random.patch
 extra/0005-virtio-rng-ask-for-more-data-if-queue-is-not-fully-d.patch
+extra/0001-target-i386-do-not-read-write-MSR_TSC_AUX-from-KVM-i.patch
-- 
2.1.4