[xen master] x86/spec-ctrl: Enumeration for IBPB_RET

[patchbot@xxxxxxx]

commit 24496558e650535bdbd22cc04731e82276cd1b3f
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Jun 14 16:18:36 2022 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Nov 8 17:26:08 2022 +0000

    x86/spec-ctrl: Enumeration for IBPB_RET
    
    The IBPB_RET bit indicates that the CPU's implementation of 
MSR_PRED_CMD.IBPB
    does flush the RSB/RAS too.
    
    This is part of XSA-422 / CVE-2022-23824.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 tools/libs/light/libxl_cpuid.c              | 1 +
 tools/misc/xen-cpuid.c                      | 1 +
 xen/arch/x86/spec_ctrl.c                    | 5 +++--
 xen/include/public/arch-x86/cpufeatureset.h | 1 +
 4 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/libs/light/libxl_cpuid.c b/tools/libs/light/libxl_cpuid.c
index d5a9b35774..2aa23225f4 100644
--- a/tools/libs/light/libxl_cpuid.c
+++ b/tools/libs/light/libxl_cpuid.c
@@ -291,6 +291,7 @@ int libxl_cpuid_parse_config(libxl_cpuid_policy_list 
*cpuid, const char* str)
         {"ssb-no",       0x80000008, NA, CPUID_REG_EBX, 26,  1},
         {"psfd",         0x80000008, NA, CPUID_REG_EBX, 28,  1},
         {"btc-no",       0x80000008, NA, CPUID_REG_EBX, 29,  1},
+        {"ibpb-ret",     0x80000008, NA, CPUID_REG_EBX, 30,  1},
 
         {"nc",           0x80000008, NA, CPUID_REG_ECX,  0,  8},
         {"apicidsize",   0x80000008, NA, CPUID_REG_ECX, 12,  4},
diff --git a/tools/misc/xen-cpuid.c b/tools/misc/xen-cpuid.c
index 390ac1dafe..d5833e9ce8 100644
--- a/tools/misc/xen-cpuid.c
+++ b/tools/misc/xen-cpuid.c
@@ -161,6 +161,7 @@ static const char *const str_e8b[32] =
     [24] = "amd-ssbd",         [25] = "virt-ssbd",
     [26] = "ssb-no",
     [28] = "psfd",             [29] = "btc-no",
+    [30] = "ibpb-ret",
 };
 
 static const char *const str_7d0[32] =
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index 4e53056624..0c3503c9cd 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -420,7 +420,7 @@ static void __init print_details(enum ind_thunk thunk, 
uint64_t caps)
      * Hardware read-only information, stating immunity to certain issues, or
      * suggestions of which mitigation to use.
      */
-    printk("  Hardware hints:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
+    printk("  Hardware hints:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
            (caps & ARCH_CAPS_RDCL_NO)                        ? " RDCL_NO"      
  : "",
            (caps & ARCH_CAPS_IBRS_ALL)                       ? " IBRS_ALL"     
  : "",
            (caps & ARCH_CAPS_RSBA)                           ? " RSBA"         
  : "",
@@ -437,7 +437,8 @@ static void __init print_details(enum ind_thunk thunk, 
uint64_t caps)
            (e8b  & cpufeat_mask(X86_FEATURE_STIBP_ALWAYS))   ? " STIBP_ALWAYS" 
  : "",
            (e8b  & cpufeat_mask(X86_FEATURE_IBRS_FAST))      ? " IBRS_FAST"    
  : "",
            (e8b  & cpufeat_mask(X86_FEATURE_IBRS_SAME_MODE)) ? " 
IBRS_SAME_MODE" : "",
-           (e8b  & cpufeat_mask(X86_FEATURE_BTC_NO))         ? " BTC_NO"       
  : "");
+           (e8b  & cpufeat_mask(X86_FEATURE_BTC_NO))         ? " BTC_NO"       
  : "",
+           (e8b  & cpufeat_mask(X86_FEATURE_IBPB_RET))       ? " IBPB_RET"     
  : "");
 
     /* Hardware features which need driving to mitigate issues. */
     printk("  Hardware features:%s%s%s%s%s%s%s%s%s%s%s%s\n",
diff --git a/xen/include/public/arch-x86/cpufeatureset.h 
b/xen/include/public/arch-x86/cpufeatureset.h
index 42f48a8ae2..02675e9c75 100644
--- a/xen/include/public/arch-x86/cpufeatureset.h
+++ b/xen/include/public/arch-x86/cpufeatureset.h
@@ -269,6 +269,7 @@ XEN_CPUFEATURE(VIRT_SSBD,     8*32+25) /*!  
MSR_VIRT_SPEC_CTRL.SSBD */
 XEN_CPUFEATURE(SSB_NO,        8*32+26) /*A  Hardware not vulnerable to SSB */
 XEN_CPUFEATURE(PSFD,          8*32+28) /*S  MSR_SPEC_CTRL.PSFD */
 XEN_CPUFEATURE(BTC_NO,        8*32+29) /*A  Hardware not vulnerable to Branch 
Type Confusion */
+XEN_CPUFEATURE(IBPB_RET,      8*32+30) /*A  IBPB clears RSB/RAS too. */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:0.edx, word 9 */
 XEN_CPUFEATURE(AVX512_4VNNIW, 9*32+ 2) /*A  AVX512 Neural Network Instructions 
*/
--
generated by git-patchbot for /home/xen/git/xen.git#master