[PATCH v2 05/10] x86/boot: Record MSR_ARCH_CAPS for the Raw and Host CPU policy

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Extend x86_cpu_policy_fill_native() with a read of ARCH_CAPS based on the
CPUID information just read, removing the specially handling in
calculate_raw_cpu_policy().

Right now, the only use of x86_cpu_policy_fill_native() outside of Xen is the
unit tests.  Getting MSR data in this context is left to whomever first
encounters a genuine need to have it.

Extend generic_identify() to read ARCH_CAPS into x86_capability[], which is
fed into the Host Policy.  This in turn means there's no need to special case
arch_caps in calculate_host_policy().

No practical change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>

v2:
 * Extend commit message to discuss the absence of MSRs outside of __XEN__
---
 xen/arch/x86/cpu-policy.c | 12 ------------
 xen/arch/x86/cpu/common.c |  5 +++++
 xen/lib/x86/cpuid.c       |  7 ++++++-
 3 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/xen/arch/x86/cpu-policy.c b/xen/arch/x86/cpu-policy.c
index 49f5465ec445..dfd9abd8564c 100644
--- a/xen/arch/x86/cpu-policy.c
+++ b/xen/arch/x86/cpu-policy.c
@@ -354,9 +354,6 @@ void calculate_raw_cpu_policy(void)
 
     /* 0x000000ce  MSR_INTEL_PLATFORM_INFO */
     /* Was already added by probe_cpuid_faulting() */
-
-    if ( cpu_has_arch_caps )
-        rdmsrl(MSR_ARCH_CAPABILITIES, p->arch_caps.raw);
 }
 
 static void __init calculate_host_policy(void)
@@ -409,15 +406,6 @@ static void __init calculate_host_policy(void)
     /* 0x000000ce  MSR_INTEL_PLATFORM_INFO */
     /* probe_cpuid_faulting() sanity checks presence of MISC_FEATURES_ENABLES 
*/
     p->platform_info.cpuid_faulting = cpu_has_cpuid_faulting;
-
-    /* Temporary, until we have known_features[] for feature bits in MSRs. */
-    p->arch_caps.raw = raw_cpu_policy.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 |
-         ARCH_CAPS_SBDR_SSDP_NO | ARCH_CAPS_FBSDP_NO | ARCH_CAPS_PSDP_NO |
-         ARCH_CAPS_FB_CLEAR | ARCH_CAPS_RRSBA | ARCH_CAPS_BHI_NO |
-         ARCH_CAPS_PBRSB_NO);
 }
 
 static void __init guest_common_default_feature_adjustments(uint32_t *fs)
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 9bbb385db42d..f1084bb1ed36 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -477,6 +477,11 @@ static void generic_identify(struct cpuinfo_x86 *c)
                cpuid_count(0xd, 1,
                            &c->x86_capability[FEATURESET_Da1],
                            &tmp, &tmp, &tmp);
+
+       if (test_bit(X86_FEATURE_ARCH_CAPS, c->x86_capability))
+               rdmsr(MSR_ARCH_CAPABILITIES,
+                     c->x86_capability[FEATURESET_10Al],
+                     c->x86_capability[FEATURESET_10Ah]);
 }
 
 /*
diff --git a/xen/lib/x86/cpuid.c b/xen/lib/x86/cpuid.c
index e795ce375032..07e550191448 100644
--- a/xen/lib/x86/cpuid.c
+++ b/xen/lib/x86/cpuid.c
@@ -226,7 +226,12 @@ void x86_cpu_policy_fill_native(struct cpu_policy *p)
     p->hv_limit = 0;
     p->hv2_limit = 0;
 
-    /* TODO MSRs */
+#ifdef __XEN__
+    /* TODO MSR_PLATFORM_INFO */
+
+    if ( p->feat.arch_caps )
+        rdmsrl(MSR_ARCH_CAPABILITIES, p->arch_caps.raw);
+#endif
 
     x86_cpu_policy_recalc_synth(p);
 }
-- 
2.30.2