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[xen stable-4.13] x86/spec-ctrl: CPUID/MSR definitions for Special Register Buffer Data Sampling



commit 9aefa01f458960fe9e2ccbdc79f8d9fba3d06611
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Jan 8 19:47:46 2020 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Jun 9 17:44:54 2020 +0100

    x86/spec-ctrl: CPUID/MSR definitions for Special Register Buffer Data 
Sampling
    
    This is part of XSA-320 / CVE-2020-0543
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Wei Liu <wl@xxxxxxx>
    (cherry picked from commit caab85ab58c0cdf74ab070a5de5c4df89f509ff3)
---
 docs/misc/xen-command-line.pandoc           | 8 ++++----
 tools/libxl/libxl_cpuid.c                   | 1 +
 tools/misc/xen-cpuid.c                      | 1 +
 xen/arch/x86/msr.c                          | 2 ++
 xen/arch/x86/spec_ctrl.c                    | 3 ++-
 xen/include/asm-x86/msr-index.h             | 3 +++
 xen/include/public/arch-x86/cpufeatureset.h | 1 +
 7 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/docs/misc/xen-command-line.pandoc 
b/docs/misc/xen-command-line.pandoc
index 1d9d816622..9268454297 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -483,10 +483,10 @@ accounting for hardware capabilities as enumerated via 
CPUID.
 
 Currently accepted:
 
-The Speculation Control hardware features `md-clear`, `ibrsb`, `stibp`, `ibpb`,
-`l1d-flush` and `ssbd` are used by default if available and applicable.  They 
can
-be ignored, e.g. `no-ibrsb`, at which point Xen won't use them itself, and
-won't offer them to guests.
+The Speculation Control hardware features `srbds-ctrl`, `md-clear`, `ibrsb`,
+`stibp`, `ibpb`, `l1d-flush` and `ssbd` are used by default if available and
+applicable.  They can be ignored, e.g. `no-ibrsb`, at which point Xen won't
+use them itself, and won't offer them to guests.
 
 ### cpuid_mask_cpu
 > `= fam_0f_rev_[cdefg] | fam_10_rev_[bc] | fam_11_rev_b`
diff --git a/tools/libxl/libxl_cpuid.c b/tools/libxl/libxl_cpuid.c
index 6cea4227ba..a78f08b927 100644
--- a/tools/libxl/libxl_cpuid.c
+++ b/tools/libxl/libxl_cpuid.c
@@ -213,6 +213,7 @@ int libxl_cpuid_parse_config(libxl_cpuid_policy_list 
*cpuid, const char* str)
 
         {"avx512-4vnniw",0x00000007,  0, CPUID_REG_EDX,  2,  1},
         {"avx512-4fmaps",0x00000007,  0, CPUID_REG_EDX,  3,  1},
+        {"srbds-ctrl",   0x00000007,  0, CPUID_REG_EDX,  9,  1},
         {"md-clear",     0x00000007,  0, CPUID_REG_EDX, 10,  1},
         {"cet-ibt",      0x00000007,  0, CPUID_REG_EDX, 20,  1},
         {"ibrsb",        0x00000007,  0, CPUID_REG_EDX, 26,  1},
diff --git a/tools/misc/xen-cpuid.c b/tools/misc/xen-cpuid.c
index 603e1d65fd..a09440813b 100644
--- a/tools/misc/xen-cpuid.c
+++ b/tools/misc/xen-cpuid.c
@@ -157,6 +157,7 @@ static const char *const str_7d0[32] =
     [ 2] = "avx512_4vnniw", [ 3] = "avx512_4fmaps",
     [ 4] = "fsrm",
 
+    /*  8 */                [ 9] = "srbds-ctrl",
     [10] = "md-clear",
     /* 12 */                [13] = "tsx-force-abort",
 
diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index 4b12103482..0cded3c0ad 100644
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -134,6 +134,7 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t *val)
         /* Write-only */
     case MSR_TSX_FORCE_ABORT:
     case MSR_TSX_CTRL:
+    case MSR_MCU_OPT_CTRL:
     case MSR_U_CET:
     case MSR_S_CET:
     case MSR_PL0_SSP ... MSR_INTERRUPT_SSP_TABLE:
@@ -288,6 +289,7 @@ int guest_wrmsr(struct vcpu *v, uint32_t msr, uint64_t val)
         /* Read-only */
     case MSR_TSX_FORCE_ABORT:
     case MSR_TSX_CTRL:
+    case MSR_MCU_OPT_CTRL:
     case MSR_U_CET:
     case MSR_S_CET:
     case MSR_PL0_SSP ... MSR_INTERRUPT_SSP_TABLE:
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index 6656c44aec..5fc1c6827e 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -312,12 +312,13 @@ static void __init print_details(enum ind_thunk thunk, 
uint64_t caps)
     printk("Speculative mitigation facilities:\n");
 
     /* Hardware features which pertain to speculative mitigations. */
-    printk("  Hardware features:%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
+    printk("  Hardware features:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
            (_7d0 & cpufeat_mask(X86_FEATURE_IBRSB)) ? " IBRS/IBPB" : "",
            (_7d0 & cpufeat_mask(X86_FEATURE_STIBP)) ? " STIBP"     : "",
            (_7d0 & cpufeat_mask(X86_FEATURE_L1D_FLUSH)) ? " L1D_FLUSH" : "",
            (_7d0 & cpufeat_mask(X86_FEATURE_SSBD))  ? " SSBD"      : "",
            (_7d0 & cpufeat_mask(X86_FEATURE_MD_CLEAR)) ? " MD_CLEAR" : "",
+           (_7d0 & cpufeat_mask(X86_FEATURE_SRBDS_CTRL)) ? " SRBDS_CTRL" : "",
            (e8b  & cpufeat_mask(X86_FEATURE_IBPB))  ? " IBPB"      : "",
            (caps & ARCH_CAPS_IBRS_ALL)              ? " IBRS_ALL"  : "",
            (caps & ARCH_CAPS_RDCL_NO)               ? " RDCL_NO"   : "",
diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h
index 7693c4a71a..91994669e1 100644
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -179,6 +179,9 @@
 #define MSR_IA32_VMX_TRUE_ENTRY_CTLS            0x490
 #define MSR_IA32_VMX_VMFUNC                     0x491
 
+#define MSR_MCU_OPT_CTRL                    0x00000123
+#define  MCU_OPT_CTRL_RNGDS_MITG_DIS        (_AC(1, ULL) <<  0)
+
 #define MSR_U_CET                           0x000006a0
 #define MSR_S_CET                           0x000006a2
 #define MSR_PL0_SSP                         0x000006a4
diff --git a/xen/include/public/arch-x86/cpufeatureset.h 
b/xen/include/public/arch-x86/cpufeatureset.h
index 2835688f1c..a2482c3627 100644
--- a/xen/include/public/arch-x86/cpufeatureset.h
+++ b/xen/include/public/arch-x86/cpufeatureset.h
@@ -252,6 +252,7 @@ XEN_CPUFEATURE(IBPB,          8*32+12) /*A  IBPB support 
only (no IBRS, used by
 /* Intel-defined CPU features, CPUID level 0x00000007:0.edx, word 9 */
 XEN_CPUFEATURE(AVX512_4VNNIW, 9*32+ 2) /*A  AVX512 Neural Network Instructions 
*/
 XEN_CPUFEATURE(AVX512_4FMAPS, 9*32+ 3) /*A  AVX512 Multiply Accumulation 
Single Precision */
+XEN_CPUFEATURE(SRBDS_CTRL,    9*32+ 9) /*   MSR_MCU_OPT_CTRL and 
RNGDS_MITG_DIS. */
 XEN_CPUFEATURE(MD_CLEAR,      9*32+10) /*A  VERW clears microarchitectural 
buffers */
 XEN_CPUFEATURE(TSX_FORCE_ABORT, 9*32+13) /* MSR_TSX_FORCE_ABORT.RTM_ABORT */
 XEN_CPUFEATURE(CET_IBT,       9*32+20) /*   CET - Indirect Branch Tracking */
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.13



 


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