[Qemu-devel] [PATCH 2/2] i386: Add some MSR based features on Cascadelake-Server CPU model

[Tao Xu]

As noted in
http://lists.gnu.org/archive/html/qemu-devel/2018-09/msg02212.html
Because MSR based feature has been supported by QEMU,
we add CPUID_7_0_EDX_ARCH_CAPABILITIES on Cascadelake-Server CPU
model, and add IA32_ARCH_CAPABILITIES MSR based features (RDCL_NO,
IBRS_ALL and SKIP_L1DFL_VMENTRY).

Note:
RSBA and SSBD_NO are not supported by native machines on stepping
6 of Cascadelake-Server, so we will keep the CPU model updated.

Signed-off-by: Tao Xu <address@hidden>
---
 include/hw/i386/pc.h | 16 ++++++++++++++++
 target/i386/cpu.c    |  6 +++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 95453968db..741ceefa5b 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -304,6 +304,22 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
         .driver   = "Cascadelake-Server" "-" TYPE_X86_CPU,\
         .property = "stepping",\
         .value    = "5",\
+    },{\
+        .driver   = "Cascadelake-Server" "-" TYPE_X86_CPU,\
+        .property = "arch-capabilities",\
+        .value    = "off",\
+    },{\
+        .driver   = "Cascadelake-Server" "-" TYPE_X86_CPU,\
+        .property = "rdctl-no",\
+        .value    = "off",\
+    },{\
+        .driver   = "Cascadelake-Server" "-" TYPE_X86_CPU,\
+        .property = "ibrs-all",\
+        .value    = "off",\
+    },{\
+        .driver   = "Cascadelake-Server" "-" TYPE_X86_CPU,\
+        .property = "skip-l1dfl-vmentry",\
+        .value    = "off",\
     },
 
 #define PC_COMPAT_3_0 \
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 09706ad51a..5296c73cd5 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -2499,7 +2499,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_ECX_PKU | CPUID_7_0_ECX_OSPKE |
             CPUID_7_0_ECX_AVX512VNNI,
         .features[FEAT_7_0_EDX] =
-            CPUID_7_0_EDX_SPEC_CTRL | CPUID_7_0_EDX_SPEC_CTRL_SSBD,
+            CPUID_7_0_EDX_SPEC_CTRL | CPUID_7_0_EDX_SPEC_CTRL_SSBD |
+            CPUID_7_0_EDX_ARCH_CAPABILITIES,
         /* Missing: XSAVES (not supported by some Linux versions,
                 * including v4.1 to v4.12).
                 * KVM doesn't yet expose any XSAVES state save component,
@@ -2511,6 +2512,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_XSAVE_XGETBV1,
         .features[FEAT_6_EAX] =
             CPUID_6_EAX_ARAT,
+        .features[FEAT_ARCH_CAPABILITIES] =
+            MSR_ARCH_CAP_RDCL_NO | MSR_ARCH_CAP_IBRS_ALL |
+            MSR_ARCH_CAP_SKIP_L1DFL_VMENTRY,
         .xlevel = 0x80000008,
         .model_id = "Intel Xeon Processor (Cascadelake)",
     },
-- 
2.17.1