hide FFXSR and WBNOINVD

FFXSR is used by Windows Server 2022 if available, which causes it to
die very early in boot - the feature is not supported by illumos bhyve
and we return a GP if the EFER bit is set.

WBNOINVD is also masked by default bhyve CPUID masking, though this one
is probably fine to pass through. Either way, because it is typically
masked, guests using this are basically untested (though as some
datapoints, Windows/Linux/illumos seem fine on bhyve with this bit
passed through..)

Author: iximeow

nexus/src/app/instance_platform/cpu_platform.rs

@@ -437,7 +437,8 @@ fn milan_ideal() -> CpuIdDump {
     leaf.set_syscall_sysret(true);
     leaf.set_execute_disable(true);
     leaf.set_mmx_extensions(true);
-    leaf.set_fast_fxsave_fxstor(true);
+    // illumos does not support setting EFER.FFSXR, so hide the bit
+    leaf.set_fast_fxsave_fxstor(false);
     leaf.set_1gib_pages(true);
     leaf.set_rdtscp(true);
     leaf.set_64bit_mode(true);
@@ -653,6 +654,19 @@ pub fn milan_rfd314() -> CpuIdDump {
         .set_l2_l3_cache_and_tlb_info(Some(leaf))
         .expect("can set leaf 8000_0006h");
 
+    let mut leaf = cpuid
+        .get_processor_capacity_feature_info()
+        .expect("can get leaf 8000_0008h");
+
+    // Support for `wbnoinvd` is hidden in bhyve for the time being. This would
+    // probably be fine to pass through, but it is as-yet untested. Continue
+    // hiding this instruction.
+    leaf.set_wbnoinvd(false);
+
+    cpuid
+        .set_processor_capacity_feature_info(Some(leaf))
+        .expect("can set leaf 8000_0008h");
+
     // Set up TLB information for 1GiB pages (leaf 8000_0019h)
     let mut leaf = Tlb1gbPageInfo::empty();
     leaf.set_dtlb_l1_1gb_associativity(0xF);
@@ -805,14 +819,14 @@ mod test {
             0xD, 0x2, 0x00000100, 0x00000240, 0x00000000, 0x00000000
         ),
         cpuid_leaf!(0x80000000, 0x80000021, 0x68747541, 0x444D4163, 0x69746E65),
-        cpuid_leaf!(0x80000001, 0x00A00F11, 0x40000000, 0x444001F9, 0x27D3FBFF),
+        cpuid_leaf!(0x80000001, 0x00A00F11, 0x40000000, 0x444001F9, 0x25D3FBFF),
         cpuid_leaf!(0x80000002, 0x20444D41, 0x43595045, 0x31373720, 0x36205033),
         cpuid_leaf!(0x80000003, 0x6F432D34, 0x50206572, 0x65636F72, 0x726F7373),
         cpuid_leaf!(0x80000004, 0x20202020, 0x20202020, 0x20202020, 0x00202020),
         cpuid_leaf!(0x80000005, 0xFF40FF40, 0xFF40FF40, 0x20080140, 0x20080140),
         cpuid_leaf!(0x80000006, 0x48002200, 0x68004200, 0x02006140, 0x08009140),
         cpuid_leaf!(0x80000007, 0x00000000, 0x00000000, 0x00000000, 0x00000100),
-        cpuid_leaf!(0x80000008, 0x00003030, 0x00000205, 0x00000000, 0x00000000),
+        cpuid_leaf!(0x80000008, 0x00003030, 0x00000005, 0x00000000, 0x00000000),
         cpuid_leaf!(0x8000000A, 0x00000000, 0x00000000, 0x00000000, 0x00000000),
         cpuid_leaf!(0x80000019, 0xF040F040, 0xF0400000, 0x00000000, 0x00000000),
         cpuid_leaf!(0x8000001A, 0x00000006, 0x00000000, 0x00000000, 0x00000000),
@@ -975,8 +989,6 @@ mod test {
         // had been passing the CPUID bits through
         ext_processor_features.set_skinit(true);
         ext_processor_features.set_wdt(true);
-        // TODO: Fast FXSAVE was not passed through?
-        ext_processor_features.set_fast_fxsave_fxstor(false);
         cpuid
             .set_extended_processor_and_feature_identifiers(Some(
                 ext_processor_features,
@@ -991,9 +1003,6 @@ mod test {
         // even though the MSR itself is not available to guests.
         leaf.set_inst_ret_cntr_msr(true);
 
-        // TODO: Support for `wbnoinvd` was hidden from guests by byhve?
-        leaf.set_wbnoinvd(false);
-
         // INVLPGB and RDPRU max were passed through even those instructions are not
         // supported.
         leaf.set_invlpgb_max_pages(7);