File 5b72fbbf-6-spec-ctrl-CPUID-MSR-definitions-for-... of Package xen

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File 5b72fbbf-6-spec-ctrl-CPUID-MSR-definitions-for-L1D_FLUSH.patch of Package xen (Revision d80300fa503284052d6f9c96ddcec0ff)

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Subject: x86/spec-ctrl: CPUID/MSR definitions for L1D_FLUSH
From: Andrew Cooper andrew.cooper3@citrix.com Wed Mar 28 15:21:39 2018 +0100
Date: Tue Aug 14 17:15:35 2018 +0100:
Git: fb78137bb82d3d8bcac36430b8bc331008ee3826

This is part of XSA-273 / CVE-2018-3646.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 3563fc2b2731a63fd7e8372ab0f5cef205bf8477)

diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index 763cc1d878..158b5bb919 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -489,10 +489,10 @@ accounting for hardware capabilities as enumerated via CPUID.
 
 Currently accepted:
 
-The Speculation Control hardware features `ibrsb`, `stibp`, `ibpb`, `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 `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 (AMD only)
 > `= fam_0f_rev_c | fam_0f_rev_d | fam_0f_rev_e | fam_0f_rev_f | fam_0f_rev_g | fam_10_rev_b | fam_10_rev_c | fam_11_rev_b`
diff --git a/tools/libxl/libxl_cpuid.c b/tools/libxl/libxl_cpuid.c
index 7b0f594c3d..52e16c20ed 100644
--- a/tools/libxl/libxl_cpuid.c
+++ b/tools/libxl/libxl_cpuid.c
@@ -204,6 +204,7 @@ int libxl_cpuid_parse_config(libxl_cpuid_policy_list *cpuid, const char* str)
         {"avx512-4fmaps",0x00000007,  0, CPUID_REG_EDX,  3,  1},
         {"ibrsb",        0x00000007,  0, CPUID_REG_EDX, 26,  1},
         {"stibp",        0x00000007,  0, CPUID_REG_EDX, 27,  1},
+        {"l1d-flush",    0x00000007,  0, CPUID_REG_EDX, 28,  1},
         {"arch-caps",    0x00000007,  0, CPUID_REG_EDX, 29,  1},
         {"ssbd",         0x00000007,  0, CPUID_REG_EDX, 31,  1},
 
diff --git a/tools/misc/xen-cpuid.c b/tools/misc/xen-cpuid.c
index e116339733..3888b4e158 100644
--- a/tools/misc/xen-cpuid.c
+++ b/tools/misc/xen-cpuid.c
@@ -143,7 +143,7 @@ static const char *str_7d0[32] =
     [ 2] = "avx512_4vnniw", [ 3] = "avx512_4fmaps",
 
     [26] = "ibrsb",         [27] = "stibp",
-    /* 28 */                [29] = "arch_caps",
+    [28] = "l1d_flush",     [29] = "arch_caps",
     /* 30 */                [31] = "ssbd",
 };
 
diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index beee47d0ed..5cc89e2b34 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -43,6 +43,11 @@ static int __init parse_xen_cpuid(const char *s)
             if ( !val )
                 setup_clear_cpu_cap(X86_FEATURE_STIBP);
         }
+        else if ( (val = parse_boolean("l1d-flush", s, ss)) >= 0 )
+        {
+            if ( !val )
+                setup_clear_cpu_cap(X86_FEATURE_L1D_FLUSH);
+        }
         else if ( (val = parse_boolean("ssbd", s, ss)) >= 0 )
         {
             if ( !val )
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index 7995e27218..9bcc2b6adc 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -266,14 +266,16 @@ 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\n",
+    printk("  Hardware features:%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"      : "",
            (e8b  & cpufeat_mask(X86_FEATURE_IBPB))  ? " IBPB"      : "",
            (caps & ARCH_CAPABILITIES_IBRS_ALL)      ? " IBRS_ALL"  : "",
            (caps & ARCH_CAPABILITIES_RDCL_NO)       ? " RDCL_NO"   : "",
            (caps & ARCH_CAPS_RSBA)                  ? " RSBA"      : "",
+           (caps & ARCH_CAPS_SKIP_L1DFL)            ? " SKIP_L1DFL": "",
            (caps & ARCH_CAPS_SSB_NO)                ? " SSB_NO"    : "");
 
     /* Compiled-in support which pertains to mitigations. */
diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h
index 8fbccc88a7..7235623c86 100644
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -47,8 +47,12 @@
 #define ARCH_CAPABILITIES_RDCL_NO	(_AC(1, ULL) << 0)
 #define ARCH_CAPABILITIES_IBRS_ALL	(_AC(1, ULL) << 1)
 #define ARCH_CAPS_RSBA			(_AC(1, ULL) << 2)
+#define ARCH_CAPS_SKIP_L1DFL		(_AC(1, ULL) << 3)
 #define ARCH_CAPS_SSB_NO		(_AC(1, ULL) << 4)
 
+#define MSR_FLUSH_CMD			0x0000010b
+#define FLUSH_CMD_L1D			(_AC(1, ULL) << 0)
+
 /* Intel MSRs. Some also available on other CPUs */
 #define MSR_IA32_PERFCTR0		0x000000c1
 #define MSR_IA32_A_PERFCTR0		0x000004c1
diff --git a/xen/include/public/arch-x86/cpufeatureset.h b/xen/include/public/arch-x86/cpufeatureset.h
index f1a5ed93e0..9f4c8246a9 100644
--- a/xen/include/public/arch-x86/cpufeatureset.h
+++ b/xen/include/public/arch-x86/cpufeatureset.h
@@ -244,6 +244,7 @@ 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(IBRSB,         9*32+26) /*A  IBRS and IBPB support (used by Intel) */
 XEN_CPUFEATURE(STIBP,         9*32+27) /*A  STIBP */
+XEN_CPUFEATURE(L1D_FLUSH,     9*32+28) /*   MSR_FLUSH_CMD and L1D flush. */
 XEN_CPUFEATURE(ARCH_CAPS,     9*32+29) /*   IA32_ARCH_CAPABILITIES MSR */
 XEN_CPUFEATURE(SSBD,          9*32+31) /*A  MSR_SPEC_CTRL.SSBD available */

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File 5b72fbbf-6-spec-ctrl-CPUID-MSR-definitions-for-L1D_FLUSH.patch of Package xen (Revision d80300fa503284052d6f9c96ddcec0ff)

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