File xsa273-6.patch of Package xen
x86/spec-ctrl: CPUID/MSR definitions for L1D_FLUSH
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>
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -496,10 +496,10 @@ accounting for hardware capabilities as
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`
--- a/tools/libxl/libxl_cpuid.c
+++ b/tools/libxl/libxl_cpuid.c
@@ -204,6 +204,7 @@ int libxl_cpuid_parse_config(libxl_cpuid
{"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},
--- a/tools/misc/xen-cpuid.c
+++ b/tools/misc/xen-cpuid.c
@@ -165,7 +165,7 @@ static const char *str_7d0[32] =
[4 ... 25] = "REZ",
[26] = "ibrsb", [27] = "stibp",
- [28] = "REZ", [29] = "arch_caps",
+ [28] = "l1d_flush", [29] = "arch_caps",
[30] = "REZ", [31] = "ssbd",
};
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -43,6 +43,11 @@ static int __init parse_xen_cpuid(const
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 )
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -250,14 +250,16 @@ static void __init print_details(enum in
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. */
--- 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
--- 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) /
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 */
