[xen master] amd: remove VIRT_SC_MSR_HVM synthetic feature

[patchbot@xxxxxxx]

commit e6440e2a72776149bacf3ab72c6453f5b72dea5f
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Tue Nov 15 14:26:56 2022 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Nov 16 00:18:42 2022 +0000

    amd: remove VIRT_SC_MSR_HVM synthetic feature
    
    With the previous bugfix, X86_FEATURE_VIRT_SC_MSR_HVM is no longer
    needed and can be replaced with an __initdata variable.  This also
    leaves asm/cpufeatures.h as it was in 4.16 which will simplify
    backports.
    
    No functional change intended.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Release-acked-by: Henry Wang <Henry.Wang@xxxxxxx>
    
    Rewrite commit message.  Move amd_virt_spec_ctrl into __initdata.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/cpu/amd.c                 | 1 +
 xen/arch/x86/cpuid.c                   | 9 +++++----
 xen/arch/x86/include/asm/amd.h         | 1 +
 xen/arch/x86/include/asm/cpufeatures.h | 2 +-
 xen/arch/x86/spec_ctrl.c               | 7 +++----
 5 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/cpu/amd.c b/xen/arch/x86/cpu/amd.c
index a332087604..070060d90b 100644
--- a/xen/arch/x86/cpu/amd.c
+++ b/xen/arch/x86/cpu/amd.c
@@ -49,6 +49,7 @@ boolean_param("allow_unsafe", opt_allow_unsafe);
 /* Signal whether the ACPI C1E quirk is required. */
 bool __read_mostly amd_acpi_c1e_quirk;
 bool __ro_after_init amd_legacy_ssbd;
+bool __initdata amd_virt_spec_ctrl;
 
 static inline int rdmsr_amd_safe(unsigned int msr, unsigned int *lo,
                                 unsigned int *hi)
diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index 822f9ace10..acc2f606ce 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -3,6 +3,7 @@
 #include <xen/param.h>
 #include <xen/sched.h>
 #include <xen/nospec.h>
+#include <asm/amd.h>
 #include <asm/cpuid.h>
 #include <asm/hvm/hvm.h>
 #include <asm/hvm/nestedhvm.h>
@@ -543,9 +544,9 @@ static void __init calculate_hvm_max_policy(void)
 
     /*
      * VIRT_SSBD is exposed in the default policy as a result of
-     * VIRT_SC_MSR_HVM being set, it also needs exposing in the max policy.
+     * amd_virt_spec_ctrl being set, it also needs exposing in the max policy.
      */
-    if ( boot_cpu_has(X86_FEATURE_VIRT_SC_MSR_HVM) )
+    if ( amd_virt_spec_ctrl )
         __set_bit(X86_FEATURE_VIRT_SSBD, hvm_featureset);
 
     /*
@@ -606,9 +607,9 @@ static void __init calculate_hvm_def_policy(void)
 
     /*
      * Only expose VIRT_SSBD if AMD_SSBD is not available, and thus
-     * VIRT_SC_MSR_HVM is set.
+     * amd_virt_spec_ctrl is set.
      */
-    if ( boot_cpu_has(X86_FEATURE_VIRT_SC_MSR_HVM) )
+    if ( amd_virt_spec_ctrl )
         __set_bit(X86_FEATURE_VIRT_SSBD, hvm_featureset);
 
     sanitise_featureset(hvm_featureset);
diff --git a/xen/arch/x86/include/asm/amd.h b/xen/arch/x86/include/asm/amd.h
index 6a42f68542..a975d3de26 100644
--- a/xen/arch/x86/include/asm/amd.h
+++ b/xen/arch/x86/include/asm/amd.h
@@ -152,6 +152,7 @@ extern bool amd_acpi_c1e_quirk;
 void amd_check_disable_c1e(unsigned int port, u8 value);
 
 extern bool amd_legacy_ssbd;
+extern bool amd_virt_spec_ctrl;
 bool amd_setup_legacy_ssbd(void);
 void amd_set_legacy_ssbd(bool enable);
 
diff --git a/xen/arch/x86/include/asm/cpufeatures.h 
b/xen/arch/x86/include/asm/cpufeatures.h
index c68ced1b82..865f110986 100644
--- a/xen/arch/x86/include/asm/cpufeatures.h
+++ b/xen/arch/x86/include/asm/cpufeatures.h
@@ -24,7 +24,7 @@ XEN_CPUFEATURE(APERFMPERF,        X86_SYNTH( 8)) /* 
APERFMPERF */
 XEN_CPUFEATURE(MFENCE_RDTSC,      X86_SYNTH( 9)) /* MFENCE synchronizes RDTSC 
*/
 XEN_CPUFEATURE(XEN_SMEP,          X86_SYNTH(10)) /* SMEP gets used by Xen 
itself */
 XEN_CPUFEATURE(XEN_SMAP,          X86_SYNTH(11)) /* SMAP gets used by Xen 
itself */
-XEN_CPUFEATURE(VIRT_SC_MSR_HVM,   X86_SYNTH(12)) /* MSR_VIRT_SPEC_CTRL exposed 
to HVM */
+/* Bit 12 unused. */
 XEN_CPUFEATURE(IND_THUNK_LFENCE,  X86_SYNTH(13)) /* Use IND_THUNK_LFENCE */
 XEN_CPUFEATURE(IND_THUNK_JMP,     X86_SYNTH(14)) /* Use IND_THUNK_JMP */
 XEN_CPUFEATURE(SC_NO_BRANCH_HARDEN, X86_SYNTH(15)) /* (Disable) Conditional 
branch hardening */
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index a0835143e3..a320b81947 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -515,12 +515,11 @@ static void __init print_details(enum ind_thunk thunk, 
uint64_t caps)
            (boot_cpu_has(X86_FEATURE_SC_MSR_HVM) ||
             boot_cpu_has(X86_FEATURE_SC_RSB_HVM) ||
             boot_cpu_has(X86_FEATURE_IBPB_ENTRY_HVM) ||
-            boot_cpu_has(X86_FEATURE_VIRT_SC_MSR_HVM) ||
+            amd_virt_spec_ctrl ||
             opt_eager_fpu || opt_md_clear_hvm)       ? ""               : " 
None",
            boot_cpu_has(X86_FEATURE_SC_MSR_HVM)      ? " MSR_SPEC_CTRL" : "",
            (boot_cpu_has(X86_FEATURE_SC_MSR_HVM) ||
-            boot_cpu_has(X86_FEATURE_VIRT_SC_MSR_HVM)) ? " MSR_VIRT_SPEC_CTRL"
-                                                       : "",
+            amd_virt_spec_ctrl)                      ? " MSR_VIRT_SPEC_CTRL" : 
"",
            boot_cpu_has(X86_FEATURE_SC_RSB_HVM)      ? " RSB"           : "",
            opt_eager_fpu                             ? " EAGER_FPU"     : "",
            opt_md_clear_hvm                          ? " MD_CLEAR"      : "",
@@ -1256,7 +1255,7 @@ void __init init_speculation_mitigations(void)
     /* Support VIRT_SPEC_CTRL.SSBD if AMD_SSBD is not available. */
     if ( opt_msr_sc_hvm && !cpu_has_amd_ssbd &&
          (cpu_has_virt_ssbd || (amd_legacy_ssbd && amd_setup_legacy_ssbd())) )
-        setup_force_cpu_cap(X86_FEATURE_VIRT_SC_MSR_HVM);
+        amd_virt_spec_ctrl = true;
 
     /* Figure out default_xen_spec_ctrl. */
     if ( has_spec_ctrl && ibrs )
--
generated by git-patchbot for /home/xen/git/xen.git#master