File xsa435-0-38.patch of Package xen.30330

From 70553000d6b44dd7c271a35932b0b3e1f22c5532 Mon Sep 17 00:00:00 2001
From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Fri, 12 May 2023 15:37:02 +0100
Subject: x86/boot: Record MSR_ARCH_CAPS for the Raw and Host CPU policy

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@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/cpu-policy.c
+++ b/xen/arch/x86/cpu-policy.c
@@ -340,9 +340,6 @@ static void __init calculate_raw_policy(
 
     /* 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)
@@ -395,15 +392,6 @@ static void __init calculate_host_policy
     /* 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_feature_adjustments(uint32_t *fs)
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -434,6 +434,11 @@ static void generic_identify(struct cpui
 		cpuid_count(0xd, 1,
 			    &c->x86_capability[cpufeat_word(X86_FEATURE_XSAVEOPT)],
 			    &tmp, &tmp, &tmp);
+
+	if (test_bit(X86_FEATURE_ARCH_CAPS, c->x86_capability))
+		rdmsr(MSR_ARCH_CAPABILITIES,
+		      c->x86_capability[FEATURESET_m10Al],
+		      c->x86_capability[FEATURESET_m10Ah]);
 }
 
 /*
--- a/xen/lib/x86/cpuid.c
+++ b/xen/lib/x86/cpuid.c
@@ -222,7 +222,12 @@ void x86_cpu_policy_fill_native(struct c
                           ARRAY_SIZE(p->extd.raw) - 1); ++i )
         cpuid_leaf(0x80000000 + i, &p->extd.raw[i]);
 
-    /* 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);
 }