fix(vmm): Set FDP_EXCPTN_ONLY and ZERO_FCS_FDS

zulinx86 · roypat · commit 5cbc900bf399 · 2023-07-07T09:57:25.000Z
Sets FDP_EXCPTN_ONLY bit (CPUID.7h.0:EBX[6]) and ZERO_FCS_FDS bit (CPUID.7h.0:EBX[13]) in Intel's CPUID normalization as recommended in kernel doc. For more details, please refer to https://lore.kernel.org/all/20220322110712.222449-3-pbonzini@redhat.com/ Signed-off-by: Takahiro Itazuri <itazur@amazon.com>
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -13,6 +13,11 @@
 - Added a `cpu-template-helper` tool for assisting with creating and managing
   custom CPU templates.
 
+### Changed
+
+- Set FDP_EXCPTN_ONLY bit (CPUID.7h.0:EBX[6]) and ZERO_FCS_FDS bit
+  (CPUID.7h.0:EBX[13]) in Intel's CPUID normalization process.
+
 ### Fixed
 
 - Fixed feature flags in T2S CPU template on Intel Ice Lake.
diff --git a/docs/cpu_templates/cpuid-normalization.md b/docs/cpu_templates/cpuid-normalization.md
@@ -30,10 +30,12 @@ See also: [boot protocol settings](boot-protocol.md)
 ## Intel-specific CPUID normalization
 
 | Description                                                    | Leaf                               | Subleaf | Register           | Bits  |
-|----------------------------------------------------------------|:----------------------------------:|:-------:|:------------------:|:----:|
+|----------------------------------------------------------------|:----------------------------------:|:-------:|:------------------:|:-----:|
 | Update deterministic cache parameters                          | 0x4                                | all     | EAX                | 31:14 |
 | Disable Intel Turbo Boost technology                           | 0x6                                | -       | EAX                | 1     |
 | Disable frequency selection                                    | 0x6                                | -       | ECX                | 3     |
+| Set FDP_EXCPTN_ONLY bit                                        | 0x7                                | 0x0     | EBX                | 6     |
+| Set "Deprecates FPU CS and FPU DS values" bit                  | 0x7                                | 0x0     | EBX                | 13    |
 | Disable performance monitoring                                 | 0xa                                | -       | EAX, EBX, ECX, EDX | all   |
 | Update brand string to use a default format and real frequency | 0x80000002, 0x80000003, 0x80000004 | -       | EAX, EBX, ECX, EDX | all   |
 
diff --git a/resources/tests/cpu_template_helper/fingerprint_INTEL_CASCADELAKE_4.14host.json b/resources/tests/cpu_template_helper/fingerprint_INTEL_CASCADELAKE_4.14host.json
@@ -270,7 +270,7 @@
           },
           {
             "register": "ebx",
-            "bitmap": "0b11010001100111110100011110101011"
+            "bitmap": "0b11010001100111110110011111101011"
           },
           {
             "register": "ecx",
diff --git a/resources/tests/cpu_template_helper/fingerprint_INTEL_CASCADELAKE_5.10host.json b/resources/tests/cpu_template_helper/fingerprint_INTEL_CASCADELAKE_5.10host.json
@@ -270,7 +270,7 @@
           },
           {
             "register": "ebx",
-            "bitmap": "0b11010001100111110100011110101011"
+            "bitmap": "0b11010001100111110110011111101011"
           },
           {
             "register": "ecx",
diff --git a/resources/tests/cpu_template_helper/fingerprint_INTEL_ICELAKE_4.14host.json b/resources/tests/cpu_template_helper/fingerprint_INTEL_ICELAKE_4.14host.json
@@ -270,7 +270,7 @@
           },
           {
             "register": "ebx",
-            "bitmap": "0b11110001101111110000011110101011"
+            "bitmap": "0b11110001101111110010011111101011"
           },
           {
             "register": "ecx",
diff --git a/resources/tests/cpu_template_helper/fingerprint_INTEL_ICELAKE_5.10host.json b/resources/tests/cpu_template_helper/fingerprint_INTEL_ICELAKE_5.10host.json
@@ -270,7 +270,7 @@
           },
           {
             "register": "ebx",
-            "bitmap": "0b11110001101111110000011110101011"
+            "bitmap": "0b11110001101111110010011111101011"
           },
           {
             "register": "ecx",
diff --git a/resources/tests/cpu_template_helper/fingerprint_INTEL_SKYLAKE_4.14host.json b/resources/tests/cpu_template_helper/fingerprint_INTEL_SKYLAKE_4.14host.json
@@ -270,7 +270,7 @@
           },
           {
             "register": "ebx",
-            "bitmap": "0b11010001100111110100111110111011"
+            "bitmap": "0b11010001100111110110111111111011"
           },
           {
             "register": "ecx",
diff --git a/resources/tests/cpu_template_helper/fingerprint_INTEL_SKYLAKE_5.10host.json b/resources/tests/cpu_template_helper/fingerprint_INTEL_SKYLAKE_5.10host.json
@@ -270,7 +270,7 @@
           },
           {
             "register": "ebx",
-            "bitmap": "0b11010001100111110100111110111011"
+            "bitmap": "0b11010001100111110110111111111011"
           },
           {
             "register": "ecx",
diff --git a/resources/tests/static_cpu_templates/c3.json b/resources/tests/static_cpu_templates/c3.json
@@ -26,7 +26,7 @@
       "modifiers": [
         {
           "register": "ebx",
-          "bitmap": "0b000000000x0x000000x000x0x00000xx"
+          "bitmap": "0b000000000x0x000000x000x0xx0000xx"
         },
         {
           "register": "ecx",
diff --git a/resources/tests/static_cpu_templates/t2.json b/resources/tests/static_cpu_templates/t2.json
@@ -26,7 +26,7 @@
       "modifiers": [
         {
           "register": "ebx",
-          "bitmap": "0b00000000000x000000000x1xx0x0x0xx"
+          "bitmap": "0b00000000000x000000x00x1xxxx0x0xx"
         },
         {
           "register": "ecx",
diff --git a/resources/tests/static_cpu_templates/t2a.json b/resources/tests/static_cpu_templates/t2a.json
@@ -26,7 +26,7 @@
       "modifiers": [
         {
           "register": "ebx",
-          "bitmap": "0b00000000000x000000000x1xx0x0x0xx"
+          "bitmap": "0b00000000000x000000x00x1xxxx0x0xx"
         },
         {
           "register": "ecx",
diff --git a/resources/tests/static_cpu_templates/t2cl.json b/resources/tests/static_cpu_templates/t2cl.json
@@ -26,7 +26,7 @@
       "modifiers": [
         {
           "register": "ebx",
-          "bitmap": "0b00000000000x000000000x1xx0x0x0xx"
+          "bitmap": "0b00000000000x000000x00x1xxxx0x0xx"
         },
         {
           "register": "ecx",
diff --git a/resources/tests/static_cpu_templates/t2s.json b/resources/tests/static_cpu_templates/t2s.json
@@ -26,7 +26,7 @@
       "modifiers": [
         {
           "register": "ebx",
-          "bitmap": "0b00000000000x000000000x1xx0x0x0xx"
+          "bitmap": "0b00000000000x000000x00x1xxxx0x0xx"
         },
         {
           "register": "ecx",
diff --git a/src/vmm/src/cpu_config/x86_64/cpuid/intel/normalize.rs b/src/vmm/src/cpu_config/x86_64/cpuid/intel/normalize.rs
@@ -18,6 +18,9 @@ pub enum NormalizeCpuidError {
     /// Leaf 0x6 is missing from CPUID.
     #[error("Leaf 0x6 is missing from CPUID.")]
     MissingLeaf6,
+    /// Leaf 0x7 / subleaf 0 is missing from CPUID.
+    #[error("Leaf 0x7 / subleaf 0 is missing from CPUID.")]
+    MissingLeaf7,
     /// Leaf 0xA is missing from CPUID.
     #[error("Leaf 0xA is missing from CPUID.")]
     MissingLeafA,
@@ -85,6 +88,7 @@ impl super::IntelCpuid {
     ) -> Result<(), NormalizeCpuidError> {
         self.update_deterministic_cache_entry(cpu_count, cpus_per_core)?;
         self.update_power_management_entry()?;
+        self.update_extended_feature_flags_entry()?;
         self.update_performance_monitoring_entry()?;
         self.update_brand_string_entry()?;
 
@@ -197,6 +201,22 @@ impl super::IntelCpuid {
         Ok(())
     }
 
+    /// Update structured extended feature flags enumeration leaf
+    fn update_extended_feature_flags_entry(&mut self) -> Result<(), NormalizeCpuidError> {
+        let leaf_7_0 = self
+            .get_mut(&CpuidKey::subleaf(0x7, 0))
+            .ok_or(NormalizeCpuidError::MissingLeaf7)?;
+
+        // Set FDP_EXCPTN_ONLY bit (bit 6) and ZERO_FCS_FDS bit (bit 13) as recommended in kernel
+        // doc. These bits are reserved in AMD.
+        // https://lore.kernel.org/all/20220322110712.222449-3-pbonzini@redhat.com/
+        // https://github.com/torvalds/linux/commit/45016721de3c714902c6f475b705e10ae0bdd801
+        set_bit(&mut leaf_7_0.result.ebx, 6, true);
+        set_bit(&mut leaf_7_0.result.ebx, 13, true);
+
+        Ok(())
+    }
+
     /// Update performance monitoring entry
     fn update_performance_monitoring_entry(&mut self) -> Result<(), NormalizeCpuidError> {
         let leaf_a = self
@@ -422,4 +442,30 @@ mod tests {
             }),
         );
     }
+
+    #[test]
+    fn test_update_extended_feature_flags_entry() {
+        let mut cpuid =
+            crate::cpu_config::x86_64::cpuid::IntelCpuid(std::collections::BTreeMap::from([(
+                crate::cpu_config::x86_64::cpuid::CpuidKey {
+                    leaf: 0x7,
+                    subleaf: 0,
+                },
+                crate::cpu_config::x86_64::cpuid::CpuidEntry {
+                    flags: crate::cpu_config::x86_64::cpuid::KvmCpuidFlags::SIGNIFICANT_INDEX,
+                    ..Default::default()
+                },
+            )]));
+
+        cpuid.update_extended_feature_flags_entry().unwrap();
+
+        let leaf_7_0 = cpuid
+            .get(&crate::cpu_config::x86_64::cpuid::CpuidKey {
+                leaf: 0x7,
+                subleaf: 0,
+            })
+            .unwrap();
+        assert!((leaf_7_0.result.ebx & (1 << 6)) > 0);
+        assert!((leaf_7_0.result.ebx & (1 << 13)) > 0);
+    }
 }
diff --git a/src/vmm/src/cpu_config/x86_64/static_cpu_templates/c3.rs b/src/vmm/src/cpu_config/x86_64/static_cpu_templates/c3.rs
@@ -49,7 +49,7 @@ pub fn c3() -> CustomCpuTemplate {
                     CpuidRegisterModifier {
                         register: CpuidRegister::Ebx,
                         bitmap: RegisterValueFilter {
-                            filter: 0b11111111101011111101110101111100,
+                            filter: 0b11111111101011111101110100111100,
                             value: 0b00000000000000000000000000000000,
                         },
                     },
diff --git a/src/vmm/src/cpu_config/x86_64/static_cpu_templates/t2.rs b/src/vmm/src/cpu_config/x86_64/static_cpu_templates/t2.rs
@@ -49,7 +49,7 @@ pub fn t2() -> CustomCpuTemplate {
                     CpuidRegisterModifier {
                         register: CpuidRegister::Ebx,
                         bitmap: RegisterValueFilter {
-                            filter: 0b11111111111011111111101001010100,
+                            filter: 0b11111111111011111101101000010100,
                             value: 0b00000000000000000000001000000000,
                         },
                     },
diff --git a/src/vmm/src/cpu_config/x86_64/static_cpu_templates/t2a.rs b/src/vmm/src/cpu_config/x86_64/static_cpu_templates/t2a.rs
@@ -49,7 +49,7 @@ pub fn t2a() -> CustomCpuTemplate {
                     CpuidRegisterModifier {
                         register: CpuidRegister::Ebx,
                         bitmap: RegisterValueFilter {
-                            filter: 0b11111111111011111111101001010100,
+                            filter: 0b11111111111011111101101000010100,
                             value: 0b00000000000000000000001000000000,
                         },
                     },
diff --git a/src/vmm/src/cpu_config/x86_64/static_cpu_templates/t2cl.rs b/src/vmm/src/cpu_config/x86_64/static_cpu_templates/t2cl.rs
@@ -50,7 +50,7 @@ pub fn t2cl() -> CustomCpuTemplate {
                     CpuidRegisterModifier {
                         register: CpuidRegister::Ebx,
                         bitmap: RegisterValueFilter {
-                            filter: 0b11111111111011111111101001010100,
+                            filter: 0b11111111111011111101101000010100,
                             value: 0b00000000000000000000001000000000,
                         },
                     },
diff --git a/src/vmm/src/cpu_config/x86_64/static_cpu_templates/t2s.rs b/src/vmm/src/cpu_config/x86_64/static_cpu_templates/t2s.rs
@@ -50,7 +50,7 @@ pub fn t2s() -> CustomCpuTemplate {
                     CpuidRegisterModifier {
                         register: CpuidRegister::Ebx,
                         bitmap: RegisterValueFilter {
-                            filter: 0b11111111111011111111101001010100,
+                            filter: 0b11111111111011111101101000010100,
                             value: 0b00000000000000000000001000000000,
                         },
                     },
diff --git a/tests/integration_tests/build/test_coverage.py b/tests/integration_tests/build/test_coverage.py
@@ -27,7 +27,7 @@ def is_on_skylake():
 if utils.is_io_uring_supported():
     COVERAGE_DICT = {"Intel": 83.59, "AMD": 83.18, "ARM": 83.04}
 else:
-    COVERAGE_DICT = {"Intel": 80.85, "AMD": 80.39, "ARM": 80.05}
+    COVERAGE_DICT = {"Intel": 80.90, "AMD": 80.39, "ARM": 80.05}
 
 PROC_MODEL = proc.proc_type()
 
diff --git a/tests/integration_tests/functional/test_cpu_features.py b/tests/integration_tests/functional/test_cpu_features.py
@@ -855,7 +855,6 @@ def check_masked_features(test_microvm, cpu_template):
                 (1 << 3) |  # BMI1
                 (1 << 4) |  # HLE
                 (1 << 5) |  # AVX2
-                (1 << 6) |  # FPDP
                 (1 << 8) |  # BMI2
                 (1 << 10) | # INVPCID
                 (1 << 11) | # RTM
@@ -941,7 +940,6 @@ def check_masked_features(test_microvm, cpu_template):
             (0x7, 0x0, "ebx",
                 (1 << 2) |  # SGX
                 (1 << 4) |  # HLE
-                (1 << 6) |  # FPDP
                 (1 << 11) | # RTM
                 (1 << 12) | # RDT_M
                 (1 << 14) | # MPX

Original file line number	Diff line number	Diff line change
`@@ -270,7 +270,7 @@`
`270`	`270`	`},`
`271`	`271`	`{`
`272`	`272`	`"register": "ebx",`
`273`		`- "bitmap": "0b11010001100111110100011110101011"`
	`273`	`+ "bitmap": "0b11010001100111110110011111101011"`
`274`	`274`	`},`
`275`	`275`	`{`
`276`	`276`	`"register": "ecx",`
Original file line number	Diff line number	Diff line change
`@@ -26,7 +26,7 @@`
`26`	`26`	`"modifiers": [`
`27`	`27`	`{`
`28`	`28`	`"register": "ebx",`
`29`		`- "bitmap": "0b000000000x0x000000x000x0x00000xx"`
	`29`	`+ "bitmap": "0b000000000x0x000000x000x0xx0000xx"`
`30`	`30`	`},`
`31`	`31`	`{`
`32`	`32`	`"register": "ecx",`