[xen staging-4.14] x86/msr: Expose MSR_ARCH_CAPS in the raw and host policies

[patchbot@xxxxxxx]

commit 62549f81869638a65efe879d23c9c4573b7e45d4
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Jun 11 11:37:53 2021 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Aug 3 19:14:18 2023 +0100

    x86/msr: Expose MSR_ARCH_CAPS in the raw and host policies
    
    MSR_ARCH_CAPS is still not supported for guests yet (other than the hardware
    domain), until the toolstack learns how to construct an MSR policy.
    
    However, we want access to the host ARCH_CAPS_TSX_CTRL value in particular 
for
    testing purposes.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    (cherry picked from commit b672695e748869b2e2e2cb03f671f12003d2b079)
    
    Also the remnants of:
    
      x86: Expose more MSR_ARCH_CAPS to hwdom
      (cherry picked from commit e83cd54611fec5b7a539fa1281a14319143490e6)
    
      x86/spec-ctrl: Enumeration for PBRSB_NO
      (cherry picked from commit b874e47eb13feb75be3ee7b5dc4ae9c97d80d774)
    
    which have both partially been backported already.
---
 xen/arch/x86/msr.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index 576235e507..7b2add4f8d 100644
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -47,8 +47,13 @@ struct msr_policy __read_mostly hvm_def_msr_policy;
 
 static void __init calculate_raw_policy(void)
 {
+    struct msr_policy *mp = &raw_msr_policy;
+
     /* 0x000000ce  MSR_INTEL_PLATFORM_INFO */
     /* Was already added by probe_cpuid_faulting() */
+
+    if ( cpu_has_arch_caps )
+        rdmsrl(MSR_ARCH_CAPABILITIES, mp->arch_caps.raw);
 }
 
 static void __init calculate_host_policy(void)
@@ -60,6 +65,12 @@ static void __init calculate_host_policy(void)
     /* 0x000000ce  MSR_INTEL_PLATFORM_INFO */
     /* probe_cpuid_faulting() sanity checks presence of MISC_FEATURES_ENABLES 
*/
     mp->platform_info.cpuid_faulting = cpu_has_cpuid_faulting;
+
+    /* Temporary, until we have known_features[] for feature bits in MSRs. */
+    mp->arch_caps.raw &=
+        (ARCH_CAPS_RDCL_NO | ARCH_CAPS_IBRS_ALL | ARCH_CAPS_RSBA |
+         ARCH_CAPS_SKIP_L1DFL | ARCH_CAPS_SSB_NO | ARCH_CAPS_MDS_NO |
+         ARCH_CAPS_IF_PSCHANGE_MC_NO | ARCH_CAPS_TSX_CTRL | ARCH_CAPS_TAA_NO);
 }
 
 static void __init calculate_pv_max_policy(void)
@@ -67,6 +78,8 @@ static void __init calculate_pv_max_policy(void)
     struct msr_policy *mp = &pv_max_msr_policy;
 
     *mp = host_msr_policy;
+
+    mp->arch_caps.raw = 0; /* Not supported yet. */
 }
 
 static void __init calculate_pv_def_policy(void)
@@ -84,6 +97,8 @@ static void __init calculate_hvm_max_policy(void)
 
     /* It's always possible to emulate CPUID faulting for HVM guests */
     mp->platform_info.cpuid_faulting = true;
+
+    mp->arch_caps.raw = 0; /* Not supported yet. */
 }
 
 static void __init calculate_hvm_def_policy(void)
--
generated by git-patchbot for /home/xen/git/xen.git#staging-4.14