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

[patchbot@xxxxxxx]

commit b672695e748869b2e2e2cb03f671f12003d2b079
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Jun 11 11:37:53 2021 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Jun 15 20:50:32 2021 +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>
---
 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 374f92b2c5..72bbe46949 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