* [PATCH 4.19 01/34] Revert "x86/speculation: Add RSB VM Exit protections"
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 02/34] Revert "x86/cpu: Add a steppings field to struct x86_cpu_id" Greg Kroah-Hartman
` (37 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Suleiman Souhlal <suleiman@google.com>
This reverts commit b6c5011934a15762cd694e36fe74f2f2f93eac9b.
In order to apply IBRS mitigation for Retbleed, PBRSB mitigations must be
reverted and the reapplied, so the backports can look sane.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/admin-guide/hw-vuln/spectre.rst | 8 ---
arch/x86/include/asm/cpufeatures.h | 2
arch/x86/include/asm/msr-index.h | 4 -
arch/x86/include/asm/nospec-branch.h | 15 ------
arch/x86/kernel/cpu/bugs.c | 61 --------------------------
arch/x86/kernel/cpu/common.c | 14 +----
arch/x86/kvm/vmx.c | 6 +-
7 files changed, 7 insertions(+), 103 deletions(-)
--- a/Documentation/admin-guide/hw-vuln/spectre.rst
+++ b/Documentation/admin-guide/hw-vuln/spectre.rst
@@ -422,14 +422,6 @@ The possible values in this file are:
'RSB filling' Protection of RSB on context switch enabled
============= ===========================================
- - EIBRS Post-barrier Return Stack Buffer (PBRSB) protection status:
-
- =========================== =======================================================
- 'PBRSB-eIBRS: SW sequence' CPU is affected and protection of RSB on VMEXIT enabled
- 'PBRSB-eIBRS: Vulnerable' CPU is vulnerable
- 'PBRSB-eIBRS: Not affected' CPU is not affected by PBRSB
- =========================== =======================================================
-
Full mitigation might require a microcode update from the CPU
vendor. When the necessary microcode is not available, the kernel will
report vulnerability.
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -283,7 +283,6 @@
#define X86_FEATURE_CQM_MBM_LOCAL (11*32+ 3) /* LLC Local MBM monitoring */
#define X86_FEATURE_FENCE_SWAPGS_USER (11*32+ 4) /* "" LFENCE in user entry SWAPGS path */
#define X86_FEATURE_FENCE_SWAPGS_KERNEL (11*32+ 5) /* "" LFENCE in kernel entry SWAPGS path */
-#define X86_FEATURE_RSB_VMEXIT_LITE (11*32+ 6) /* "" Fill RSB on VM exit when EIBRS is enabled */
/* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */
#define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */
@@ -397,6 +396,5 @@
#define X86_BUG_SRBDS X86_BUG(24) /* CPU may leak RNG bits if not mitigated */
#define X86_BUG_MMIO_STALE_DATA X86_BUG(25) /* CPU is affected by Processor MMIO Stale Data vulnerabilities */
#define X86_BUG_MMIO_UNKNOWN X86_BUG(26) /* CPU is too old and its MMIO Stale Data status is unknown */
-#define X86_BUG_EIBRS_PBRSB X86_BUG(27) /* EIBRS is vulnerable to Post Barrier RSB Predictions */
#endif /* _ASM_X86_CPUFEATURES_H */
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -120,10 +120,6 @@
* bit available to control VERW
* behavior.
*/
-#define ARCH_CAP_PBRSB_NO BIT(24) /*
- * Not susceptible to Post-Barrier
- * Return Stack Buffer Predictions.
- */
#define MSR_IA32_FLUSH_CMD 0x0000010b
#define L1D_FLUSH BIT(0) /*
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -70,14 +70,6 @@
add $(BITS_PER_LONG/8) * nr, sp;
#endif
-/* Sequence to mitigate PBRSB on eIBRS CPUs */
-#define __ISSUE_UNBALANCED_RET_GUARD(sp) \
- call 881f; \
- int3; \
-881: \
- add $(BITS_PER_LONG/8), sp; \
- lfence;
-
#ifdef __ASSEMBLY__
/*
@@ -293,13 +285,6 @@ static inline void vmexit_fill_RSB(void)
: "=r" (loops), ASM_CALL_CONSTRAINT
: : "memory" );
#endif
- asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE("jmp 920f",
- __stringify(__ISSUE_UNBALANCED_RET_GUARD(%0)),
- X86_FEATURE_RSB_VMEXIT_LITE)
- "920:"
- : ASM_CALL_CONSTRAINT
- : : "memory" );
}
static __always_inline
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1046,49 +1046,6 @@ static enum spectre_v2_mitigation __init
return SPECTRE_V2_RETPOLINE;
}
-static void __init spectre_v2_determine_rsb_fill_type_at_vmexit(enum spectre_v2_mitigation mode)
-{
- /*
- * Similar to context switches, there are two types of RSB attacks
- * after VM exit:
- *
- * 1) RSB underflow
- *
- * 2) Poisoned RSB entry
- *
- * When retpoline is enabled, both are mitigated by filling/clearing
- * the RSB.
- *
- * When IBRS is enabled, while #1 would be mitigated by the IBRS branch
- * prediction isolation protections, RSB still needs to be cleared
- * because of #2. Note that SMEP provides no protection here, unlike
- * user-space-poisoned RSB entries.
- *
- * eIBRS should protect against RSB poisoning, but if the EIBRS_PBRSB
- * bug is present then a LITE version of RSB protection is required,
- * just a single call needs to retire before a RET is executed.
- */
- switch (mode) {
- case SPECTRE_V2_NONE:
- /* These modes already fill RSB at vmexit */
- case SPECTRE_V2_LFENCE:
- case SPECTRE_V2_RETPOLINE:
- case SPECTRE_V2_EIBRS_RETPOLINE:
- return;
-
- case SPECTRE_V2_EIBRS_LFENCE:
- case SPECTRE_V2_EIBRS:
- if (boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB)) {
- setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT_LITE);
- pr_info("Spectre v2 / PBRSB-eIBRS: Retire a single CALL on VMEXIT\n");
- }
- return;
- }
-
- pr_warn_once("Unknown Spectre v2 mode, disabling RSB mitigation at VM exit");
- dump_stack();
-}
-
static void __init spectre_v2_select_mitigation(void)
{
enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
@@ -1181,8 +1138,6 @@ static void __init spectre_v2_select_mit
setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW);
pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n");
- spectre_v2_determine_rsb_fill_type_at_vmexit(mode);
-
/*
* Retpoline means the kernel is safe because it has no indirect
* branches. Enhanced IBRS protects firmware too, so, enable restricted
@@ -1918,19 +1873,6 @@ static char *ibpb_state(void)
return "";
}
-static char *pbrsb_eibrs_state(void)
-{
- if (boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB)) {
- if (boot_cpu_has(X86_FEATURE_RSB_VMEXIT_LITE) ||
- boot_cpu_has(X86_FEATURE_RETPOLINE))
- return ", PBRSB-eIBRS: SW sequence";
- else
- return ", PBRSB-eIBRS: Vulnerable";
- } else {
- return ", PBRSB-eIBRS: Not affected";
- }
-}
-
static ssize_t spectre_v2_show_state(char *buf)
{
if (spectre_v2_enabled == SPECTRE_V2_LFENCE)
@@ -1943,13 +1885,12 @@ static ssize_t spectre_v2_show_state(cha
spectre_v2_enabled == SPECTRE_V2_EIBRS_LFENCE)
return sprintf(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and SMT\n");
- return sprintf(buf, "%s%s%s%s%s%s%s\n",
+ return sprintf(buf, "%s%s%s%s%s%s\n",
spectre_v2_strings[spectre_v2_enabled],
ibpb_state(),
boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
stibp_state(),
boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
- pbrsb_eibrs_state(),
spectre_v2_module_string());
}
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -954,8 +954,7 @@ static void identify_cpu_without_cpuid(s
#define MSBDS_ONLY BIT(5)
#define NO_SWAPGS BIT(6)
#define NO_ITLB_MULTIHIT BIT(7)
-#define NO_EIBRS_PBRSB BIT(8)
-#define NO_MMIO BIT(9)
+#define NO_MMIO BIT(8)
#define VULNWL(_vendor, _family, _model, _whitelist) \
{ X86_VENDOR_##_vendor, _family, _model, X86_FEATURE_ANY, _whitelist }
@@ -997,7 +996,7 @@ static const __initconst struct x86_cpu_
VULNWL_INTEL(ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
VULNWL_INTEL(ATOM_GOLDMONT_X, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
- VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB),
+ VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
/*
* Technically, swapgs isn't serializing on AMD (despite it previously
@@ -1007,9 +1006,7 @@ static const __initconst struct x86_cpu_
* good enough for our purposes.
*/
- VULNWL_INTEL(ATOM_TREMONT, NO_EIBRS_PBRSB),
- VULNWL_INTEL(ATOM_TREMONT_L, NO_EIBRS_PBRSB),
- VULNWL_INTEL(ATOM_TREMONT_X, NO_ITLB_MULTIHIT | NO_EIBRS_PBRSB),
+ VULNWL_INTEL(ATOM_TREMONT_X, NO_ITLB_MULTIHIT),
/* AMD Family 0xf - 0x12 */
VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
@@ -1169,11 +1166,6 @@ static void __init cpu_set_bug_bits(stru
setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN);
}
- if (cpu_has(c, X86_FEATURE_IBRS_ENHANCED) &&
- !cpu_matches(cpu_vuln_whitelist, NO_EIBRS_PBRSB) &&
- !(ia32_cap & ARCH_CAP_PBRSB_NO))
- setup_force_cpu_bug(X86_BUG_EIBRS_PBRSB);
-
if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
return;
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10988,9 +10988,6 @@ static void __noclone vmx_vcpu_run(struc
#endif
);
- /* Eliminate branch target predictions from guest mode */
- vmexit_fill_RSB();
-
vmx_enable_fb_clear(vmx);
/*
@@ -11013,6 +11010,9 @@ static void __noclone vmx_vcpu_run(struc
x86_spec_ctrl_restore_host(vmx->spec_ctrl, 0);
+ /* Eliminate branch target predictions from guest mode */
+ vmexit_fill_RSB();
+
/* All fields are clean at this point */
if (static_branch_unlikely(&enable_evmcs))
current_evmcs->hv_clean_fields |=
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 02/34] Revert "x86/cpu: Add a steppings field to struct x86_cpu_id"
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 01/34] Revert "x86/speculation: Add RSB VM Exit protections" Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 03/34] x86/cpufeature: Add facility to check for min microcode revisions Greg Kroah-Hartman
` (36 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Suleiman Souhlal <suleiman@google.com>
This reverts commit 6f2f28e71e6af993761b7a70bd2402a8d2096acf.
This is commit e9d7144597b10ff13ff2264c059f7d4a7fbc89ac upstream. Reverting this
commit makes the following patches apply cleanly. This patch is then reapplied.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu_device_id.h | 27 ---------------------------
arch/x86/kernel/cpu/match.c | 7 +------
include/linux/mod_devicetable.h | 6 ------
3 files changed, 1 insertion(+), 39 deletions(-)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -9,33 +9,6 @@
#include <linux/mod_devicetable.h>
-#define X86_STEPPINGS(mins, maxs) GENMASK(maxs, mins)
-
-/**
- * X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE - Base macro for CPU matching
- * @_vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
- * The name is expanded to X86_VENDOR_@_vendor
- * @_family: The family number or X86_FAMILY_ANY
- * @_model: The model number, model constant or X86_MODEL_ANY
- * @_steppings: Bitmask for steppings, stepping constant or X86_STEPPING_ANY
- * @_feature: A X86_FEATURE bit or X86_FEATURE_ANY
- * @_data: Driver specific data or NULL. The internal storage
- * format is unsigned long. The supplied value, pointer
- * etc. is casted to unsigned long internally.
- *
- * Backport version to keep the SRBDS pile consistant. No shorter variants
- * required for this.
- */
-#define X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(_vendor, _family, _model, \
- _steppings, _feature, _data) { \
- .vendor = X86_VENDOR_##_vendor, \
- .family = _family, \
- .model = _model, \
- .steppings = _steppings, \
- .feature = _feature, \
- .driver_data = (unsigned long) _data \
-}
-
extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
#endif
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -34,18 +34,13 @@ const struct x86_cpu_id *x86_match_cpu(c
const struct x86_cpu_id *m;
struct cpuinfo_x86 *c = &boot_cpu_data;
- for (m = match;
- m->vendor | m->family | m->model | m->steppings | m->feature;
- m++) {
+ for (m = match; m->vendor | m->family | m->model | m->feature; m++) {
if (m->vendor != X86_VENDOR_ANY && c->x86_vendor != m->vendor)
continue;
if (m->family != X86_FAMILY_ANY && c->x86 != m->family)
continue;
if (m->model != X86_MODEL_ANY && c->x86_model != m->model)
continue;
- if (m->steppings != X86_STEPPING_ANY &&
- !(BIT(c->x86_stepping) & m->steppings))
- continue;
if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
continue;
return m;
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -621,10 +621,6 @@ struct mips_cdmm_device_id {
/*
* MODULE_DEVICE_TABLE expects this struct to be called x86cpu_device_id.
* Although gcc seems to ignore this error, clang fails without this define.
- *
- * Note: The ordering of the struct is different from upstream because the
- * static initializers in kernels < 5.7 still use C89 style while upstream
- * has been converted to proper C99 initializers.
*/
#define x86cpu_device_id x86_cpu_id
struct x86_cpu_id {
@@ -633,7 +629,6 @@ struct x86_cpu_id {
__u16 model;
__u16 feature; /* bit index */
kernel_ulong_t driver_data;
- __u16 steppings;
};
#define X86_FEATURE_MATCH(x) \
@@ -642,7 +637,6 @@ struct x86_cpu_id {
#define X86_VENDOR_ANY 0xffff
#define X86_FAMILY_ANY 0
#define X86_MODEL_ANY 0
-#define X86_STEPPING_ANY 0
#define X86_FEATURE_ANY 0 /* Same as FPU, you can't test for that */
/*
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 03/34] x86/cpufeature: Add facility to check for min microcode revisions
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 01/34] Revert "x86/speculation: Add RSB VM Exit protections" Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 02/34] Revert "x86/cpu: Add a steppings field to struct x86_cpu_id" Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 04/34] x86/cpufeature: Fix various quality problems in the <asm/cpu_device_hd.h> header Greg Kroah-Hartman
` (35 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Thomas Gleixner, Kan Liang,
Peter Zijlstra (Intel),
Borislav Petkov, Linus Torvalds, eranian, Ingo Molnar,
Suleiman Souhlal, Andi Kleen
From: Kan Liang <kan.liang@linux.intel.com>
For bug workarounds or checks, it is useful to check for specific
microcode revisions.
Add a new generic function to match the CPU with stepping.
Add the other function to check the min microcode revisions for
the matched CPU.
A new table format is introduced to facilitate the quirk to
fill the related information.
This does not change the existing x86_cpu_id because it's an ABI
shared with modules, and also has quite different requirements,
as in no wildcards, but everything has to be matched exactly.
Originally-by: Andi Kleen <ak@linux.intel.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: eranian@google.com
Link: https://lkml.kernel.org/r/1549319013-4522-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu_device_id.h | 28 ++++++++++++++++++++++++++++
arch/x86/kernel/cpu/match.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 59 insertions(+)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -11,4 +11,32 @@
extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
+/*
+ * Match specific microcode revisions.
+ *
+ * vendor/family/model/stepping must be all set.
+ *
+ * Only checks against the boot CPU. When mixed-stepping configs are
+ * valid for a CPU model, add a quirk for every valid stepping and
+ * do the fine-tuning in the quirk handler.
+ */
+
+struct x86_cpu_desc {
+ __u8 x86_family;
+ __u8 x86_vendor;
+ __u8 x86_model;
+ __u8 x86_stepping;
+ __u32 x86_microcode_rev;
+};
+
+#define INTEL_CPU_DESC(mod, step, rev) { \
+ .x86_family = 6, \
+ .x86_vendor = X86_VENDOR_INTEL, \
+ .x86_model = mod, \
+ .x86_stepping = step, \
+ .x86_microcode_rev = rev, \
+}
+
+extern bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table);
+
#endif
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -48,3 +48,34 @@ const struct x86_cpu_id *x86_match_cpu(c
return NULL;
}
EXPORT_SYMBOL(x86_match_cpu);
+
+static const struct x86_cpu_desc *
+x86_match_cpu_with_stepping(const struct x86_cpu_desc *match)
+{
+ struct cpuinfo_x86 *c = &boot_cpu_data;
+ const struct x86_cpu_desc *m;
+
+ for (m = match; m->x86_family | m->x86_model; m++) {
+ if (c->x86_vendor != m->x86_vendor)
+ continue;
+ if (c->x86 != m->x86_family)
+ continue;
+ if (c->x86_model != m->x86_model)
+ continue;
+ if (c->x86_stepping != m->x86_stepping)
+ continue;
+ return m;
+ }
+ return NULL;
+}
+
+bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table)
+{
+ const struct x86_cpu_desc *res = x86_match_cpu_with_stepping(table);
+
+ if (!res || res->x86_microcode_rev > boot_cpu_data.microcode)
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(x86_cpu_has_min_microcode_rev);
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 04/34] x86/cpufeature: Fix various quality problems in the <asm/cpu_device_hd.h> header
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (2 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 03/34] x86/cpufeature: Add facility to check for min microcode revisions Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 05/34] x86/devicetable: Move x86 specific macro out of generic code Greg Kroah-Hartman
` (34 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Thomas Gleixner, Andi Kleen,
Kan Liang, Peter Zijlstra (Intel),
Borislav Petkov, Linus Torvalds, linux-kernel, Ingo Molnar,
Suleiman Souhlal
From: Ingo Molnar <mingo@kernel.org>
Thomas noticed that the new arch/x86/include/asm/cpu_device_id.h header is
a train-wreck that didn't incorporate review feedback like not using __u8
in kernel-only headers.
While at it also fix all the *other* problems this header has:
- Use canonical names for the header guards. It's inexplicable why a non-standard
guard was used.
- Don't define the header guard to 1. Plus annotate the closing #endif as done
absolutely every other header. Again, an inexplicable source of noise.
- Move the kernel API calls provided by this header next to each other, there's
absolutely no reason to have them spread apart in the header.
- Align the INTEL_CPU_DESC() macro initializations vertically, this is easier to
read and it's also the canonical style.
- Actually name the macro arguments properly: instead of 'mod, step, rev',
spell out 'model, stepping, revision' - it's not like we have a lack of
characters in this header.
- Actually make arguments macro-safe - again it's inexplicable why it wasn't
done properly to begin with.
Quite amazing how many problems a 41 lines header can contain.
This kind of code quality is unacceptable, and it slipped through the
review net of 2 developers and 2 maintainers, including myself, until
Thomas noticed it. :-/
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu_device_id.h | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _CPU_DEVICE_ID
-#define _CPU_DEVICE_ID 1
+#ifndef _ASM_X86_CPU_DEVICE_ID
+#define _ASM_X86_CPU_DEVICE_ID
/*
* Declare drivers belonging to specific x86 CPUs
@@ -9,8 +9,6 @@
#include <linux/mod_devicetable.h>
-extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
-
/*
* Match specific microcode revisions.
*
@@ -22,21 +20,22 @@ extern const struct x86_cpu_id *x86_matc
*/
struct x86_cpu_desc {
- __u8 x86_family;
- __u8 x86_vendor;
- __u8 x86_model;
- __u8 x86_stepping;
- __u32 x86_microcode_rev;
+ u8 x86_family;
+ u8 x86_vendor;
+ u8 x86_model;
+ u8 x86_stepping;
+ u32 x86_microcode_rev;
};
-#define INTEL_CPU_DESC(mod, step, rev) { \
- .x86_family = 6, \
- .x86_vendor = X86_VENDOR_INTEL, \
- .x86_model = mod, \
- .x86_stepping = step, \
- .x86_microcode_rev = rev, \
+#define INTEL_CPU_DESC(model, stepping, revision) { \
+ .x86_family = 6, \
+ .x86_vendor = X86_VENDOR_INTEL, \
+ .x86_model = (model), \
+ .x86_stepping = (stepping), \
+ .x86_microcode_rev = (revision), \
}
+extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
extern bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table);
-#endif
+#endif /* _ASM_X86_CPU_DEVICE_ID */
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 05/34] x86/devicetable: Move x86 specific macro out of generic code
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (3 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 04/34] x86/cpufeature: Fix various quality problems in the <asm/cpu_device_hd.h> header Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 06/34] x86/cpu: Add consistent CPU match macros Greg Kroah-Hartman
` (33 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Thomas Gleixner, Borislav Petkov,
Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Thomas Gleixner <tglx@linutronix.de>
commit ba5bade4cc0d2013cdf5634dae554693c968a090 upstream.
There is no reason that this gunk is in a generic header file. The wildcard
defines need to stay as they are required by file2alias.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lkml.kernel.org/r/20200320131508.736205164@linutronix.de
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[suleiman: vmx.c moved]
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu_device_id.h | 13 ++++++++++++-
arch/x86/kvm/svm.c | 1 +
arch/x86/kvm/vmx.c | 1 +
drivers/cpufreq/acpi-cpufreq.c | 1 +
drivers/cpufreq/amd_freq_sensitivity.c | 1 +
include/linux/mod_devicetable.h | 4 +---
6 files changed, 17 insertions(+), 4 deletions(-)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -6,10 +6,21 @@
* Declare drivers belonging to specific x86 CPUs
* Similar in spirit to pci_device_id and related PCI functions
*/
-
#include <linux/mod_devicetable.h>
/*
+ * The wildcard initializers are in mod_devicetable.h because
+ * file2alias needs them. Sigh.
+ */
+
+#define X86_FEATURE_MATCH(x) { \
+ .vendor = X86_VENDOR_ANY, \
+ .family = X86_FAMILY_ANY, \
+ .model = X86_MODEL_ANY, \
+ .feature = x, \
+}
+
+/*
* Match specific microcode revisions.
*
* vendor/family/model/stepping must be all set.
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -50,6 +50,7 @@
#include <asm/kvm_para.h>
#include <asm/irq_remapping.h>
#include <asm/spec-ctrl.h>
+#include <asm/cpu_device_id.h>
#include <asm/virtext.h>
#include "trace.h"
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -41,6 +41,7 @@
#include <asm/asm.h>
#include <asm/cpu.h>
+#include <asm/cpu_device_id.h>
#include <asm/io.h>
#include <asm/desc.h>
#include <asm/vmx.h>
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -47,6 +47,7 @@
#include <asm/msr.h>
#include <asm/processor.h>
#include <asm/cpufeature.h>
+#include <asm/cpu_device_id.h>
MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
MODULE_DESCRIPTION("ACPI Processor P-States Driver");
--- a/drivers/cpufreq/amd_freq_sensitivity.c
+++ b/drivers/cpufreq/amd_freq_sensitivity.c
@@ -21,6 +21,7 @@
#include <asm/msr.h>
#include <asm/cpufeature.h>
+#include <asm/cpu_device_id.h>
#include "cpufreq_ondemand.h"
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -631,9 +631,7 @@ struct x86_cpu_id {
kernel_ulong_t driver_data;
};
-#define X86_FEATURE_MATCH(x) \
- { X86_VENDOR_ANY, X86_FAMILY_ANY, X86_MODEL_ANY, x }
-
+/* Wild cards for x86_cpu_id::vendor, family, model and feature */
#define X86_VENDOR_ANY 0xffff
#define X86_FAMILY_ANY 0
#define X86_MODEL_ANY 0
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 06/34] x86/cpu: Add consistent CPU match macros
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (4 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 05/34] x86/devicetable: Move x86 specific macro out of generic code Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 07/34] x86/cpu: Add a steppings field to struct x86_cpu_id Greg Kroah-Hartman
` (32 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Thomas Gleixner, Borislav Petkov,
Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Thomas Gleixner <tglx@linutronix.de>
commit 20d437447c0089cda46c683db219d3b4e2cde40e upstream.
Finding all places which build x86_cpu_id match tables is tedious and the
logic is hidden in lots of differently named macro wrappers.
Most of these initializer macros use plain C89 initializers which rely on
the ordering of the struct members. So new members could only be added at
the end of the struct, but that's ugly as hell and C99 initializers are
really the right thing to use.
Provide a set of macros which:
- Have a proper naming scheme, starting with X86_MATCH_
- Use C99 initializers
The set of provided macros are all subsets of the base macro
X86_MATCH_VENDOR_FAM_MODEL_FEATURE()
which allows to supply all possible selection criteria:
vendor, family, model, feature
The other macros shorten this to avoid typing all arguments when they are
not needed and would require one of the _ANY constants. They have been
created due to the requirements of the existing usage sites.
Also add a few model constants for Centaur CPUs and QUARK.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lkml.kernel.org/r/20200320131508.826011988@linutronix.de
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu_device_id.h | 140 ++++++++++++++++++++++++++++++++---
arch/x86/include/asm/intel-family.h | 6 +
arch/x86/kernel/cpu/match.c | 13 ++-
3 files changed, 146 insertions(+), 13 deletions(-)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -5,21 +5,143 @@
/*
* Declare drivers belonging to specific x86 CPUs
* Similar in spirit to pci_device_id and related PCI functions
- */
-#include <linux/mod_devicetable.h>
-
-/*
+ *
* The wildcard initializers are in mod_devicetable.h because
* file2alias needs them. Sigh.
*/
+#include <linux/mod_devicetable.h>
+/* Get the INTEL_FAM* model defines */
+#include <asm/intel-family.h>
+/* And the X86_VENDOR_* ones */
+#include <asm/processor.h>
-#define X86_FEATURE_MATCH(x) { \
- .vendor = X86_VENDOR_ANY, \
- .family = X86_FAMILY_ANY, \
- .model = X86_MODEL_ANY, \
- .feature = x, \
+/* Centaur FAM6 models */
+#define X86_CENTAUR_FAM6_C7_A 0xa
+#define X86_CENTAUR_FAM6_C7_D 0xd
+#define X86_CENTAUR_FAM6_NANO 0xf
+
+/**
+ * X86_MATCH_VENDOR_FAM_MODEL_FEATURE - Base macro for CPU matching
+ * @_vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
+ * The name is expanded to X86_VENDOR_@_vendor
+ * @_family: The family number or X86_FAMILY_ANY
+ * @_model: The model number, model constant or X86_MODEL_ANY
+ * @_feature: A X86_FEATURE bit or X86_FEATURE_ANY
+ * @_data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * Use only if you need all selectors. Otherwise use one of the shorter
+ * macros of the X86_MATCH_* family. If there is no matching shorthand
+ * macro, consider to add one. If you really need to wrap one of the macros
+ * into another macro at the usage site for good reasons, then please
+ * start this local macro with X86_MATCH to allow easy grepping.
+ */
+#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(_vendor, _family, _model, \
+ _feature, _data) { \
+ .vendor = X86_VENDOR_##_vendor, \
+ .family = _family, \
+ .model = _model, \
+ .feature = _feature, \
+ .driver_data = (unsigned long) _data \
}
+/**
+ * X86_MATCH_VENDOR_FAM_FEATURE - Macro for matching vendor, family and CPU feature
+ * @vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
+ * The name is expanded to X86_VENDOR_@vendor
+ * @family: The family number or X86_FAMILY_ANY
+ * @feature: A X86_FEATURE bit
+ * @data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * All other missing arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
+ * set to wildcards.
+ */
+#define X86_MATCH_VENDOR_FAM_FEATURE(vendor, family, feature, data) \
+ X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, \
+ X86_MODEL_ANY, feature, data)
+
+/**
+ * X86_MATCH_VENDOR_FEATURE - Macro for matching vendor and CPU feature
+ * @vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
+ * The name is expanded to X86_VENDOR_@vendor
+ * @feature: A X86_FEATURE bit
+ * @data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * All other missing arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
+ * set to wildcards.
+ */
+#define X86_MATCH_VENDOR_FEATURE(vendor, feature, data) \
+ X86_MATCH_VENDOR_FAM_FEATURE(vendor, X86_FAMILY_ANY, feature, data)
+
+/**
+ * X86_MATCH_FEATURE - Macro for matching a CPU feature
+ * @feature: A X86_FEATURE bit
+ * @data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * All other missing arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
+ * set to wildcards.
+ */
+#define X86_MATCH_FEATURE(feature, data) \
+ X86_MATCH_VENDOR_FEATURE(ANY, feature, data)
+
+/* Transitional to keep the existing code working */
+#define X86_FEATURE_MATCH(feature) X86_MATCH_FEATURE(feature, NULL)
+
+/**
+ * X86_MATCH_VENDOR_FAM_MODEL - Match vendor, family and model
+ * @vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
+ * The name is expanded to X86_VENDOR_@vendor
+ * @family: The family number or X86_FAMILY_ANY
+ * @model: The model number, model constant or X86_MODEL_ANY
+ * @data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * All other missing arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
+ * set to wildcards.
+ */
+#define X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, data) \
+ X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, \
+ X86_FEATURE_ANY, data)
+
+/**
+ * X86_MATCH_VENDOR_FAM - Match vendor and family
+ * @vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
+ * The name is expanded to X86_VENDOR_@vendor
+ * @family: The family number or X86_FAMILY_ANY
+ * @data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * All other missing arguments to X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are
+ * set of wildcards.
+ */
+#define X86_MATCH_VENDOR_FAM(vendor, family, data) \
+ X86_MATCH_VENDOR_FAM_MODEL(vendor, family, X86_MODEL_ANY, data)
+
+/**
+ * X86_MATCH_INTEL_FAM6_MODEL - Match vendor INTEL, family 6 and model
+ * @model: The model name without the INTEL_FAM6_ prefix or ANY
+ * The model name is expanded to INTEL_FAM6_@model internally
+ * @data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * The vendor is set to INTEL, the family to 6 and all other missing
+ * arguments of X86_MATCH_VENDOR_FAM_MODEL_FEATURE() are set to wildcards.
+ *
+ * See X86_MATCH_VENDOR_FAM_MODEL_FEATURE() for further information.
+ */
+#define X86_MATCH_INTEL_FAM6_MODEL(model, data) \
+ X86_MATCH_VENDOR_FAM_MODEL(INTEL, 6, INTEL_FAM6_##model, data)
+
/*
* Match specific microcode revisions.
*
--- a/arch/x86/include/asm/intel-family.h
+++ b/arch/x86/include/asm/intel-family.h
@@ -13,6 +13,9 @@
* that group keep the CPUID for the variants sorted by model number.
*/
+/* Wildcard match for FAM6 so X86_MATCH_INTEL_FAM6_MODEL(ANY) works */
+#define INTEL_FAM6_ANY X86_MODEL_ANY
+
#define INTEL_FAM6_CORE_YONAH 0x0E
#define INTEL_FAM6_CORE2_MEROM 0x0F
@@ -101,6 +104,9 @@
#define INTEL_FAM6_XEON_PHI_KNL 0x57 /* Knights Landing */
#define INTEL_FAM6_XEON_PHI_KNM 0x85 /* Knights Mill */
+/* Family 5 */
+#define INTEL_FAM5_QUARK_X1000 0x09 /* Quark X1000 SoC */
+
/* Useful macros */
#define INTEL_CPU_FAM_ANY(_family, _model, _driver_data) \
{ \
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -16,12 +16,17 @@
* respective wildcard entries.
*
* A typical table entry would be to match a specific CPU
- * { X86_VENDOR_INTEL, 6, 0x12 }
- * or to match a specific CPU feature
- * { X86_FEATURE_MATCH(X86_FEATURE_FOOBAR) }
+ *
+ * X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6, INTEL_FAM6_BROADWELL,
+ * X86_FEATURE_ANY, NULL);
*
* Fields can be wildcarded with %X86_VENDOR_ANY, %X86_FAMILY_ANY,
- * %X86_MODEL_ANY, %X86_FEATURE_ANY or 0 (except for vendor)
+ * %X86_MODEL_ANY, %X86_FEATURE_ANY (except for vendor)
+ *
+ * asm/cpu_device_id.h contains a set of useful macros which are shortcuts
+ * for various common selections. The above can be shortened to:
+ *
+ * X86_MATCH_INTEL_FAM6_MODEL(BROADWELL, NULL);
*
* Arrays used to match for this should also be declared using
* MODULE_DEVICE_TABLE(x86cpu, ...)
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 07/34] x86/cpu: Add a steppings field to struct x86_cpu_id
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (5 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 06/34] x86/cpu: Add consistent CPU match macros Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 08/34] x86/cpufeatures: Move RETPOLINE flags to word 11 Greg Kroah-Hartman
` (31 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Mark Gross, Borislav Petkov,
Thomas Gleixner, Tony Luck, Josh Poimboeuf,
Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Mark Gross <mgross@linux.intel.com>
commit e9d7144597b10ff13ff2264c059f7d4a7fbc89ac upstream.
Intel uses the same family/model for several CPUs. Sometimes the
stepping must be checked to tell them apart.
On x86 there can be at most 16 steppings. Add a steppings bitmask to
x86_cpu_id and a X86_MATCH_VENDOR_FAMILY_MODEL_STEPPING_FEATURE macro
and support for matching against family/model/stepping.
[ bp: Massage. ]
Signed-off-by: Mark Gross <mgross@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
[cascardo: have steppings be the last member as there are initializers
that don't use named members]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[suleiman: vmx.c moved]
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu_device_id.h | 27 ++++++++++++++++++++++++---
arch/x86/kernel/cpu/match.c | 7 ++++++-
arch/x86/kvm/vmx.c | 6 +++---
arch/x86/kvm/x86.c | 4 ++--
include/linux/kvm_host.h | 2 +-
include/linux/mod_devicetable.h | 6 ++++++
6 files changed, 42 insertions(+), 10 deletions(-)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -20,12 +20,14 @@
#define X86_CENTAUR_FAM6_C7_D 0xd
#define X86_CENTAUR_FAM6_NANO 0xf
+#define X86_STEPPINGS(mins, maxs) GENMASK(maxs, mins)
/**
- * X86_MATCH_VENDOR_FAM_MODEL_FEATURE - Base macro for CPU matching
+ * X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE - Base macro for CPU matching
* @_vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
* The name is expanded to X86_VENDOR_@_vendor
* @_family: The family number or X86_FAMILY_ANY
* @_model: The model number, model constant or X86_MODEL_ANY
+ * @_steppings: Bitmask for steppings, stepping constant or X86_STEPPING_ANY
* @_feature: A X86_FEATURE bit or X86_FEATURE_ANY
* @_data: Driver specific data or NULL. The internal storage
* format is unsigned long. The supplied value, pointer
@@ -37,16 +39,35 @@
* into another macro at the usage site for good reasons, then please
* start this local macro with X86_MATCH to allow easy grepping.
*/
-#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(_vendor, _family, _model, \
- _feature, _data) { \
+#define X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(_vendor, _family, _model, \
+ _steppings, _feature, _data) { \
.vendor = X86_VENDOR_##_vendor, \
.family = _family, \
.model = _model, \
+ .steppings = _steppings, \
.feature = _feature, \
.driver_data = (unsigned long) _data \
}
/**
+ * X86_MATCH_VENDOR_FAM_MODEL_FEATURE - Macro for CPU matching
+ * @_vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
+ * The name is expanded to X86_VENDOR_@_vendor
+ * @_family: The family number or X86_FAMILY_ANY
+ * @_model: The model number, model constant or X86_MODEL_ANY
+ * @_feature: A X86_FEATURE bit or X86_FEATURE_ANY
+ * @_data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * The steppings arguments of X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE() is
+ * set to wildcards.
+ */
+#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data) \
+ X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(vendor, family, model, \
+ X86_STEPPING_ANY, feature, data)
+
+/**
* X86_MATCH_VENDOR_FAM_FEATURE - Macro for matching vendor, family and CPU feature
* @vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
* The name is expanded to X86_VENDOR_@vendor
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -39,13 +39,18 @@ const struct x86_cpu_id *x86_match_cpu(c
const struct x86_cpu_id *m;
struct cpuinfo_x86 *c = &boot_cpu_data;
- for (m = match; m->vendor | m->family | m->model | m->feature; m++) {
+ for (m = match;
+ m->vendor | m->family | m->model | m->steppings | m->feature;
+ m++) {
if (m->vendor != X86_VENDOR_ANY && c->x86_vendor != m->vendor)
continue;
if (m->family != X86_FAMILY_ANY && c->x86 != m->family)
continue;
if (m->model != X86_MODEL_ANY && c->x86_model != m->model)
continue;
+ if (m->steppings != X86_STEPPING_ANY &&
+ !(BIT(c->x86_stepping) & m->steppings))
+ continue;
if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
continue;
return m;
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2133,9 +2133,9 @@ static __always_inline void vmx_disable_
if (!vmx->disable_fb_clear)
return;
- rdmsrl(MSR_IA32_MCU_OPT_CTRL, msr);
+ msr = __rdmsr(MSR_IA32_MCU_OPT_CTRL);
msr |= FB_CLEAR_DIS;
- wrmsrl(MSR_IA32_MCU_OPT_CTRL, msr);
+ native_wrmsrl(MSR_IA32_MCU_OPT_CTRL, msr);
/* Cache the MSR value to avoid reading it later */
vmx->msr_ia32_mcu_opt_ctrl = msr;
}
@@ -2146,7 +2146,7 @@ static __always_inline void vmx_enable_f
return;
vmx->msr_ia32_mcu_opt_ctrl &= ~FB_CLEAR_DIS;
- wrmsrl(MSR_IA32_MCU_OPT_CTRL, vmx->msr_ia32_mcu_opt_ctrl);
+ native_wrmsrl(MSR_IA32_MCU_OPT_CTRL, vmx->msr_ia32_mcu_opt_ctrl);
}
static void vmx_update_fb_clear_dis(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9736,9 +9736,9 @@ void kvm_arch_end_assignment(struct kvm
}
EXPORT_SYMBOL_GPL(kvm_arch_end_assignment);
-bool kvm_arch_has_assigned_device(struct kvm *kvm)
+bool noinstr kvm_arch_has_assigned_device(struct kvm *kvm)
{
- return atomic_read(&kvm->arch.assigned_device_count);
+ return arch_atomic_read(&kvm->arch.assigned_device_count);
}
EXPORT_SYMBOL_GPL(kvm_arch_has_assigned_device);
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -928,7 +928,7 @@ static inline void kvm_arch_end_assignme
{
}
-static inline bool kvm_arch_has_assigned_device(struct kvm *kvm)
+static __always_inline bool kvm_arch_has_assigned_device(struct kvm *kvm)
{
return false;
}
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -621,6 +621,10 @@ struct mips_cdmm_device_id {
/*
* MODULE_DEVICE_TABLE expects this struct to be called x86cpu_device_id.
* Although gcc seems to ignore this error, clang fails without this define.
+ *
+ * Note: The ordering of the struct is different from upstream because the
+ * static initializers in kernels < 5.7 still use C89 style while upstream
+ * has been converted to proper C99 initializers.
*/
#define x86cpu_device_id x86_cpu_id
struct x86_cpu_id {
@@ -629,12 +633,14 @@ struct x86_cpu_id {
__u16 model;
__u16 feature; /* bit index */
kernel_ulong_t driver_data;
+ __u16 steppings;
};
/* Wild cards for x86_cpu_id::vendor, family, model and feature */
#define X86_VENDOR_ANY 0xffff
#define X86_FAMILY_ANY 0
#define X86_MODEL_ANY 0
+#define X86_STEPPING_ANY 0
#define X86_FEATURE_ANY 0 /* Same as FPU, you can't test for that */
/*
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 08/34] x86/cpufeatures: Move RETPOLINE flags to word 11
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (6 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 07/34] x86/cpu: Add a steppings field to struct x86_cpu_id Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 09/34] x86/bugs: Report AMD retbleed vulnerability Greg Kroah-Hartman
` (30 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit a883d624aed463c84c22596006e5a96f5b44db31 upstream.
In order to extend the RETPOLINE features to 4, move them to word 11
where there is still room. This mostly keeps DISABLE_RETPOLINE
simple.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpufeatures.h | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -202,8 +202,8 @@
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
#define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */
#define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enabled */
-#define X86_FEATURE_RETPOLINE ( 7*32+12) /* "" Generic Retpoline mitigation for Spectre variant 2 */
-#define X86_FEATURE_RETPOLINE_LFENCE ( 7*32+13) /* "" Use LFENCE for Spectre variant 2 */
+/* FREE! ( 7*32+12) */
+/* FREE! ( 7*32+13) */
#define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Number */
#define X86_FEATURE_CDP_L2 ( 7*32+15) /* Code and Data Prioritization L2 */
#define X86_FEATURE_MSR_SPEC_CTRL ( 7*32+16) /* "" MSR SPEC_CTRL is implemented */
@@ -283,6 +283,14 @@
#define X86_FEATURE_CQM_MBM_LOCAL (11*32+ 3) /* LLC Local MBM monitoring */
#define X86_FEATURE_FENCE_SWAPGS_USER (11*32+ 4) /* "" LFENCE in user entry SWAPGS path */
#define X86_FEATURE_FENCE_SWAPGS_KERNEL (11*32+ 5) /* "" LFENCE in kernel entry SWAPGS path */
+/* FREE! (11*32+ 6) */
+/* FREE! (11*32+ 7) */
+/* FREE! (11*32+ 8) */
+/* FREE! (11*32+ 9) */
+/* FREE! (11*32+10) */
+/* FREE! (11*32+11) */
+#define X86_FEATURE_RETPOLINE (11*32+12) /* "" Generic Retpoline mitigation for Spectre variant 2 */
+#define X86_FEATURE_RETPOLINE_LFENCE (11*32+13) /* "" Use LFENCE for Spectre variant 2 */
/* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */
#define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 09/34] x86/bugs: Report AMD retbleed vulnerability
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (7 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 08/34] x86/cpufeatures: Move RETPOLINE flags to word 11 Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 10/34] x86/bugs: Add AMD retbleed= boot parameter Greg Kroah-Hartman
` (29 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Kim Phillips, Alexandre Chartre,
Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Alexandre Chartre <alexandre.chartre@oracle.com>
commit 6b80b59b3555706508008f1f127b5412c89c7fd8 upstream.
Report that AMD x86 CPUs are vulnerable to the RETBleed (Arbitrary
Speculative Code Execution with Return Instructions) attack.
[peterz: add hygon]
[kim: invert parity; fam15h]
Co-developed-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
[cascardo: adjusted BUG numbers to match upstream]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[suleiman: Remove hygon]
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kernel/cpu/bugs.c | 13 +++++++++++++
arch/x86/kernel/cpu/common.c | 15 +++++++++++++++
drivers/base/cpu.c | 8 ++++++++
include/linux/cpu.h | 2 ++
5 files changed, 39 insertions(+)
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -404,5 +404,6 @@
#define X86_BUG_SRBDS X86_BUG(24) /* CPU may leak RNG bits if not mitigated */
#define X86_BUG_MMIO_STALE_DATA X86_BUG(25) /* CPU is affected by Processor MMIO Stale Data vulnerabilities */
#define X86_BUG_MMIO_UNKNOWN X86_BUG(26) /* CPU is too old and its MMIO Stale Data status is unknown */
+#define X86_BUG_RETBLEED X86_BUG(27) /* CPU is affected by RETBleed */
#endif /* _ASM_X86_CPUFEATURES_H */
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1899,6 +1899,11 @@ static ssize_t srbds_show_state(char *bu
return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]);
}
+static ssize_t retbleed_show_state(char *buf)
+{
+ return sprintf(buf, "Vulnerable\n");
+}
+
static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr,
char *buf, unsigned int bug)
{
@@ -1945,6 +1950,9 @@ static ssize_t cpu_show_common(struct de
case X86_BUG_MMIO_UNKNOWN:
return mmio_stale_data_show_state(buf);
+ case X86_BUG_RETBLEED:
+ return retbleed_show_state(buf);
+
default:
break;
}
@@ -2004,4 +2012,9 @@ ssize_t cpu_show_mmio_stale_data(struct
else
return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_STALE_DATA);
}
+
+ssize_t cpu_show_retbleed(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpu_show_common(dev, attr, buf, X86_BUG_RETBLEED);
+}
#endif
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1019,16 +1019,24 @@ static const __initconst struct x86_cpu_
{}
};
+#define VULNBL(vendor, family, model, blacklist) \
+ X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, blacklist)
+
#define VULNBL_INTEL_STEPPINGS(model, steppings, issues) \
X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(INTEL, 6, \
INTEL_FAM6_##model, steppings, \
X86_FEATURE_ANY, issues)
+#define VULNBL_AMD(family, blacklist) \
+ VULNBL(AMD, family, X86_MODEL_ANY, blacklist)
+
#define SRBDS BIT(0)
/* CPU is affected by X86_BUG_MMIO_STALE_DATA */
#define MMIO BIT(1)
/* CPU is affected by Shared Buffers Data Sampling (SBDS), a variant of X86_BUG_MMIO_STALE_DATA */
#define MMIO_SBDS BIT(2)
+/* CPU is affected by RETbleed, speculating where you would not expect it */
+#define RETBLEED BIT(3)
static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS),
@@ -1061,6 +1069,10 @@ static const struct x86_cpu_id cpu_vuln_
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_X, X86_STEPPING_ANY, MMIO),
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO | MMIO_SBDS),
+
+ VULNBL_AMD(0x15, RETBLEED),
+ VULNBL_AMD(0x16, RETBLEED),
+ VULNBL_AMD(0x17, RETBLEED),
{}
};
@@ -1166,6 +1178,9 @@ static void __init cpu_set_bug_bits(stru
setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN);
}
+ if (cpu_matches(cpu_vuln_blacklist, RETBLEED))
+ setup_force_cpu_bug(X86_BUG_RETBLEED);
+
if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
return;
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -577,6 +577,12 @@ ssize_t __weak cpu_show_mmio_stale_data(
return sysfs_emit(buf, "Not affected\n");
}
+ssize_t __weak cpu_show_retbleed(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "Not affected\n");
+}
+
static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
@@ -587,6 +593,7 @@ static DEVICE_ATTR(tsx_async_abort, 0444
static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
+static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
static struct attribute *cpu_root_vulnerabilities_attrs[] = {
&dev_attr_meltdown.attr,
@@ -599,6 +606,7 @@ static struct attribute *cpu_root_vulner
&dev_attr_itlb_multihit.attr,
&dev_attr_srbds.attr,
&dev_attr_mmio_stale_data.attr,
+ &dev_attr_retbleed.attr,
NULL
};
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -68,6 +68,8 @@ extern ssize_t cpu_show_srbds(struct dev
extern ssize_t cpu_show_mmio_stale_data(struct device *dev,
struct device_attribute *attr,
char *buf);
+extern ssize_t cpu_show_retbleed(struct device *dev,
+ struct device_attribute *attr, char *buf);
extern __printf(4, 5)
struct device *cpu_device_create(struct device *parent, void *drvdata,
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 10/34] x86/bugs: Add AMD retbleed= boot parameter
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (8 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 09/34] x86/bugs: Report AMD retbleed vulnerability Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 11/34] x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value Greg Kroah-Hartman
` (28 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Alexandre Chartre,
Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Alexandre Chartre <alexandre.chartre@oracle.com>
commit 7fbf47c7ce50b38a64576b150e7011ae73d54669 upstream.
Add the "retbleed=<value>" boot parameter to select a mitigation for
RETBleed. Possible values are "off", "auto" and "unret"
(JMP2RET mitigation). The default value is "auto".
Currently, "retbleed=auto" will select the unret mitigation on
AMD and Hygon and no mitigation on Intel (JMP2RET is not effective on
Intel).
[peterz: rebase; add hygon]
[jpoimboe: cleanups]
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
[cascardo: this effectively remove the UNRET mitigation as an option, so it
has to be complemented by a later pick of the same commit later. This is
done in order to pick retbleed_select_mitigation]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/admin-guide/kernel-parameters.txt | 12 +++
arch/x86/kernel/cpu/bugs.c | 74 +++++++++++++++++++++++-
2 files changed, 85 insertions(+), 1 deletion(-)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4132,6 +4132,18 @@
retain_initrd [RAM] Keep initrd memory after extraction
+ retbleed= [X86] Control mitigation of RETBleed (Arbitrary
+ Speculative Code Execution with Return Instructions)
+ vulnerability.
+
+ off - unconditionally disable
+ auto - automatically select a migitation
+
+ Selecting 'auto' will choose a mitigation method at run
+ time according to the CPU.
+
+ Not specifying this option is equivalent to retbleed=auto.
+
rfkill.default_state=
0 "airplane mode". All wifi, bluetooth, wimax, gps, fm,
etc. communication is blocked by default.
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -36,6 +36,7 @@
#include "cpu.h"
static void __init spectre_v1_select_mitigation(void);
+static void __init retbleed_select_mitigation(void);
static void __init spectre_v2_select_mitigation(void);
static void __init ssb_select_mitigation(void);
static void __init l1tf_select_mitigation(void);
@@ -111,6 +112,12 @@ void __init check_bugs(void)
/* Select the proper CPU mitigations before patching alternatives: */
spectre_v1_select_mitigation();
+ retbleed_select_mitigation();
+ /*
+ * spectre_v2_select_mitigation() relies on the state set by
+ * retbleed_select_mitigation(); specifically the STIBP selection is
+ * forced for UNRET.
+ */
spectre_v2_select_mitigation();
ssb_select_mitigation();
l1tf_select_mitigation();
@@ -706,6 +713,71 @@ static int __init nospectre_v1_cmdline(c
early_param("nospectre_v1", nospectre_v1_cmdline);
#undef pr_fmt
+#define pr_fmt(fmt) "RETBleed: " fmt
+
+enum retbleed_mitigation {
+ RETBLEED_MITIGATION_NONE,
+};
+
+enum retbleed_mitigation_cmd {
+ RETBLEED_CMD_OFF,
+ RETBLEED_CMD_AUTO,
+};
+
+const char * const retbleed_strings[] = {
+ [RETBLEED_MITIGATION_NONE] = "Vulnerable",
+};
+
+static enum retbleed_mitigation retbleed_mitigation __ro_after_init =
+ RETBLEED_MITIGATION_NONE;
+static enum retbleed_mitigation_cmd retbleed_cmd __ro_after_init =
+ RETBLEED_CMD_AUTO;
+
+static int __init retbleed_parse_cmdline(char *str)
+{
+ if (!str)
+ return -EINVAL;
+
+ if (!strcmp(str, "off"))
+ retbleed_cmd = RETBLEED_CMD_OFF;
+ else if (!strcmp(str, "auto"))
+ retbleed_cmd = RETBLEED_CMD_AUTO;
+ else
+ pr_err("Unknown retbleed option (%s). Defaulting to 'auto'\n", str);
+
+ return 0;
+}
+early_param("retbleed", retbleed_parse_cmdline);
+
+#define RETBLEED_UNTRAIN_MSG "WARNING: BTB untrained return thunk mitigation is only effective on AMD/Hygon!\n"
+#define RETBLEED_COMPILER_MSG "WARNING: kernel not compiled with RETPOLINE or -mfunction-return capable compiler!\n"
+
+static void __init retbleed_select_mitigation(void)
+{
+ if (!boot_cpu_has_bug(X86_BUG_RETBLEED) || cpu_mitigations_off())
+ return;
+
+ switch (retbleed_cmd) {
+ case RETBLEED_CMD_OFF:
+ return;
+
+ case RETBLEED_CMD_AUTO:
+ default:
+ if (!boot_cpu_has_bug(X86_BUG_RETBLEED))
+ break;
+
+ break;
+ }
+
+ switch (retbleed_mitigation) {
+ default:
+ break;
+ }
+
+ pr_info("%s\n", retbleed_strings[retbleed_mitigation]);
+}
+
+#undef pr_fmt
#define pr_fmt(fmt) "Spectre V2 : " fmt
static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =
@@ -1901,7 +1973,7 @@ static ssize_t srbds_show_state(char *bu
static ssize_t retbleed_show_state(char *buf)
{
- return sprintf(buf, "Vulnerable\n");
+ return sprintf(buf, "%s\n", retbleed_strings[retbleed_mitigation]);
}
static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr,
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 11/34] x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (9 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 10/34] x86/bugs: Add AMD retbleed= boot parameter Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 12/34] x86/entry: Remove skip_r11rcx Greg Kroah-Hartman
` (27 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit caa0ff24d5d0e02abce5e65c3d2b7f20a6617be5 upstream.
Due to TIF_SSBD and TIF_SPEC_IB the actual IA32_SPEC_CTRL value can
differ from x86_spec_ctrl_base. As such, keep a per-CPU value
reflecting the current task's MSR content.
[jpoimboe: rename]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 1 +
arch/x86/kernel/cpu/bugs.c | 28 +++++++++++++++++++++++-----
arch/x86/kernel/process.c | 2 +-
3 files changed, 25 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -307,6 +307,7 @@ static inline void indirect_branch_predi
/* The Intel SPEC CTRL MSR base value cache */
extern u64 x86_spec_ctrl_base;
+extern void write_spec_ctrl_current(u64 val);
/*
* With retpoline, we must use IBRS to restrict branch prediction
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -47,12 +47,30 @@ static void __init taa_select_mitigation
static void __init mmio_select_mitigation(void);
static void __init srbds_select_mitigation(void);
-/* The base value of the SPEC_CTRL MSR that always has to be preserved. */
+/* The base value of the SPEC_CTRL MSR without task-specific bits set */
u64 x86_spec_ctrl_base;
EXPORT_SYMBOL_GPL(x86_spec_ctrl_base);
+
+/* The current value of the SPEC_CTRL MSR with task-specific bits set */
+DEFINE_PER_CPU(u64, x86_spec_ctrl_current);
+EXPORT_SYMBOL_GPL(x86_spec_ctrl_current);
+
static DEFINE_MUTEX(spec_ctrl_mutex);
/*
+ * Keep track of the SPEC_CTRL MSR value for the current task, which may differ
+ * from x86_spec_ctrl_base due to STIBP/SSB in __speculation_ctrl_update().
+ */
+void write_spec_ctrl_current(u64 val)
+{
+ if (this_cpu_read(x86_spec_ctrl_current) == val)
+ return;
+
+ this_cpu_write(x86_spec_ctrl_current, val);
+ wrmsrl(MSR_IA32_SPEC_CTRL, val);
+}
+
+/*
* The vendor and possibly platform specific bits which can be modified in
* x86_spec_ctrl_base.
*/
@@ -1177,7 +1195,7 @@ static void __init spectre_v2_select_mit
if (spectre_v2_in_eibrs_mode(mode)) {
/* Force it so VMEXIT will restore correctly */
x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
- wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
+ write_spec_ctrl_current(x86_spec_ctrl_base);
}
switch (mode) {
@@ -1232,7 +1250,7 @@ static void __init spectre_v2_select_mit
static void update_stibp_msr(void * __unused)
{
- wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
+ write_spec_ctrl_current(x86_spec_ctrl_base);
}
/* Update x86_spec_ctrl_base in case SMT state changed. */
@@ -1475,7 +1493,7 @@ static enum ssb_mitigation __init __ssb_
x86_amd_ssb_disable();
} else {
x86_spec_ctrl_base |= SPEC_CTRL_SSBD;
- wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
+ write_spec_ctrl_current(x86_spec_ctrl_base);
}
}
@@ -1680,7 +1698,7 @@ int arch_prctl_spec_ctrl_get(struct task
void x86_spec_ctrl_setup_ap(void)
{
if (boot_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
- wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
+ write_spec_ctrl_current(x86_spec_ctrl_base);
if (ssb_mode == SPEC_STORE_BYPASS_DISABLE)
x86_amd_ssb_disable();
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -434,7 +434,7 @@ static __always_inline void __speculatio
}
if (updmsr)
- wrmsrl(MSR_IA32_SPEC_CTRL, msr);
+ write_spec_ctrl_current(msr);
}
static unsigned long speculation_ctrl_update_tif(struct task_struct *tsk)
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 12/34] x86/entry: Remove skip_r11rcx
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (10 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 11/34] x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 13/34] x86/entry: Add kernel IBRS implementation Greg Kroah-Hartman
` (26 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Borislav Petkov, Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit 1b331eeea7b8676fc5dbdf80d0a07e41be226177 upstream.
Yes, r11 and rcx have been restored previously, but since they're being
popped anyway (into rsi) might as well pop them into their own regs --
setting them to the value they already are.
Less magical code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220506121631.365070674@infradead.org
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/entry/calling.h | 10 +---------
arch/x86/entry/entry_64.S | 3 +--
2 files changed, 2 insertions(+), 11 deletions(-)
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -146,27 +146,19 @@ For 32-bit we have the following convent
.endm
-.macro POP_REGS pop_rdi=1 skip_r11rcx=0
+.macro POP_REGS pop_rdi=1
popq %r15
popq %r14
popq %r13
popq %r12
popq %rbp
popq %rbx
- .if \skip_r11rcx
- popq %rsi
- .else
popq %r11
- .endif
popq %r10
popq %r9
popq %r8
popq %rax
- .if \skip_r11rcx
- popq %rsi
- .else
popq %rcx
- .endif
popq %rdx
popq %rsi
.if \pop_rdi
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -311,8 +311,7 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
* perf profiles. Nothing jumps here.
*/
syscall_return_via_sysret:
- /* rcx and r11 are already restored (see code above) */
- POP_REGS pop_rdi=0 skip_r11rcx=1
+ POP_REGS pop_rdi=0
/*
* Now all regs are restored except RSP and RDI.
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 13/34] x86/entry: Add kernel IBRS implementation
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (11 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 12/34] x86/entry: Remove skip_r11rcx Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 14/34] x86/bugs: Optimize SPEC_CTRL MSR writes Greg Kroah-Hartman
` (25 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit 2dbb887e875b1de3ca8f40ddf26bcfe55798c609 upstream.
Implement Kernel IBRS - currently the only known option to mitigate RSB
underflow speculation issues on Skylake hardware.
Note: since IBRS_ENTER requires fuller context established than
UNTRAIN_RET, it must be placed after it. However, since UNTRAIN_RET
itself implies a RET, it must come after IBRS_ENTER. This means
IBRS_ENTER needs to also move UNTRAIN_RET.
Note 2: KERNEL_IBRS is sub-optimal for XenPV.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
[cascardo: conflict at arch/x86/entry/entry_64.S, skip_r11rcx]
[cascardo: conflict at arch/x86/entry/entry_64_compat.S]
[cascardo: conflict fixups, no ANNOTATE_NOENDBR]
[cascardo: entry fixups because of missing UNTRAIN_RET]
[cascardo: conflicts on fsgsbase]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/entry/calling.h | 58 +++++++++++++++++++++++++++++++++++++
arch/x86/entry/entry_64.S | 29 +++++++++++++++++-
arch/x86/entry/entry_64_compat.S | 11 ++++++-
arch/x86/include/asm/cpufeatures.h | 2 -
4 files changed, 97 insertions(+), 3 deletions(-)
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -6,6 +6,8 @@
#include <asm/percpu.h>
#include <asm/asm-offsets.h>
#include <asm/processor-flags.h>
+#include <asm/msr.h>
+#include <asm/nospec-branch.h>
/*
@@ -309,6 +311,62 @@ For 32-bit we have the following convent
#endif
/*
+ * IBRS kernel mitigation for Spectre_v2.
+ *
+ * Assumes full context is established (PUSH_REGS, CR3 and GS) and it clobbers
+ * the regs it uses (AX, CX, DX). Must be called before the first RET
+ * instruction (NOTE! UNTRAIN_RET includes a RET instruction)
+ *
+ * The optional argument is used to save/restore the current value,
+ * which is used on the paranoid paths.
+ *
+ * Assumes x86_spec_ctrl_{base,current} to have SPEC_CTRL_IBRS set.
+ */
+.macro IBRS_ENTER save_reg
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_KERNEL_IBRS
+ movl $MSR_IA32_SPEC_CTRL, %ecx
+
+.ifnb \save_reg
+ rdmsr
+ shl $32, %rdx
+ or %rdx, %rax
+ mov %rax, \save_reg
+ test $SPEC_CTRL_IBRS, %eax
+ jz .Ldo_wrmsr_\@
+ lfence
+ jmp .Lend_\@
+.Ldo_wrmsr_\@:
+.endif
+
+ movq PER_CPU_VAR(x86_spec_ctrl_current), %rdx
+ movl %edx, %eax
+ shr $32, %rdx
+ wrmsr
+.Lend_\@:
+.endm
+
+/*
+ * Similar to IBRS_ENTER, requires KERNEL GS,CR3 and clobbers (AX, CX, DX)
+ * regs. Must be called after the last RET.
+ */
+.macro IBRS_EXIT save_reg
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_KERNEL_IBRS
+ movl $MSR_IA32_SPEC_CTRL, %ecx
+
+.ifnb \save_reg
+ mov \save_reg, %rdx
+.else
+ movq PER_CPU_VAR(x86_spec_ctrl_current), %rdx
+ andl $(~SPEC_CTRL_IBRS), %edx
+.endif
+
+ movl %edx, %eax
+ shr $32, %rdx
+ wrmsr
+.Lend_\@:
+.endm
+
+/*
* Mitigate Spectre v1 for conditional swapgs code paths.
*
* FENCE_SWAPGS_USER_ENTRY is used in the user entry swapgs code path, to
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -235,6 +235,10 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
/* IRQs are off. */
movq %rax, %rdi
movq %rsp, %rsi
+
+ /* clobbers %rax, make sure it is after saving the syscall nr */
+ IBRS_ENTER
+
call do_syscall_64 /* returns with IRQs disabled */
TRACE_IRQS_IRETQ /* we're about to change IF */
@@ -311,6 +315,7 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
* perf profiles. Nothing jumps here.
*/
syscall_return_via_sysret:
+ IBRS_EXIT
POP_REGS pop_rdi=0
/*
@@ -684,6 +689,7 @@ GLOBAL(retint_user)
TRACE_IRQS_IRETQ
GLOBAL(swapgs_restore_regs_and_return_to_usermode)
+ IBRS_EXIT
#ifdef CONFIG_DEBUG_ENTRY
/* Assert that pt_regs indicates user mode. */
testb $3, CS(%rsp)
@@ -1249,7 +1255,13 @@ ENTRY(paranoid_entry)
*/
FENCE_SWAPGS_KERNEL_ENTRY
- ret
+ /*
+ * Once we have CR3 and %GS setup save and set SPEC_CTRL. Just like
+ * CR3 above, keep the old value in a callee saved register.
+ */
+ IBRS_ENTER save_reg=%r15
+
+ RET
END(paranoid_entry)
/*
@@ -1277,12 +1289,20 @@ ENTRY(paranoid_exit)
jmp .Lparanoid_exit_restore
.Lparanoid_exit_no_swapgs:
TRACE_IRQS_IRETQ_DEBUG
+
+ /*
+ * Must restore IBRS state before both CR3 and %GS since we need access
+ * to the per-CPU x86_spec_ctrl_shadow variable.
+ */
+ IBRS_EXIT save_reg=%r15
+
/* Always restore stashed CR3 value (see paranoid_entry) */
RESTORE_CR3 scratch_reg=%rbx save_reg=%r14
.Lparanoid_exit_restore:
jmp restore_regs_and_return_to_kernel
END(paranoid_exit)
+
/*
* Save all registers in pt_regs, and switch GS if needed.
*/
@@ -1302,6 +1322,7 @@ ENTRY(error_entry)
FENCE_SWAPGS_USER_ENTRY
/* We have user CR3. Change to kernel CR3. */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
+ IBRS_ENTER
.Lerror_entry_from_usermode_after_swapgs:
/* Put us onto the real thread stack. */
@@ -1366,6 +1387,7 @@ ENTRY(error_entry)
SWAPGS
FENCE_SWAPGS_USER_ENTRY
SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
+ IBRS_ENTER
/*
* Pretend that the exception came from user mode: set up pt_regs
@@ -1471,6 +1493,8 @@ ENTRY(nmi)
PUSH_AND_CLEAR_REGS rdx=(%rdx)
ENCODE_FRAME_POINTER
+ IBRS_ENTER
+
/*
* At this point we no longer need to worry about stack damage
* due to nesting -- we're on the normal thread stack and we're
@@ -1694,6 +1718,9 @@ end_repeat_nmi:
movq $-1, %rsi
call do_nmi
+ /* Always restore stashed SPEC_CTRL value (see paranoid_entry) */
+ IBRS_EXIT save_reg=%r15
+
/* Always restore stashed CR3 value (see paranoid_entry) */
RESTORE_CR3 scratch_reg=%r15 save_reg=%r14
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -4,7 +4,6 @@
*
* Copyright 2000-2002 Andi Kleen, SuSE Labs.
*/
-#include "calling.h"
#include <asm/asm-offsets.h>
#include <asm/current.h>
#include <asm/errno.h>
@@ -17,6 +16,8 @@
#include <linux/linkage.h>
#include <linux/err.h>
+#include "calling.h"
+
.section .entry.text, "ax"
/*
@@ -106,6 +107,8 @@ ENTRY(entry_SYSENTER_compat)
xorl %r15d, %r15d /* nospec r15 */
cld
+ IBRS_ENTER
+
/*
* SYSENTER doesn't filter flags, so we need to clear NT and AC
* ourselves. To save a few cycles, we can check whether
@@ -253,6 +256,8 @@ GLOBAL(entry_SYSCALL_compat_after_hwfram
*/
TRACE_IRQS_OFF
+ IBRS_ENTER
+
movq %rsp, %rdi
call do_fast_syscall_32
/* XEN PV guests always use IRET path */
@@ -262,6 +267,9 @@ GLOBAL(entry_SYSCALL_compat_after_hwfram
/* Opportunistic SYSRET */
sysret32_from_system_call:
TRACE_IRQS_ON /* User mode traces as IRQs on. */
+
+ IBRS_EXIT
+
movq RBX(%rsp), %rbx /* pt_regs->rbx */
movq RBP(%rsp), %rbp /* pt_regs->rbp */
movq EFLAGS(%rsp), %r11 /* pt_regs->flags (in r11) */
@@ -403,6 +411,7 @@ ENTRY(entry_INT80_compat)
* gate turned them off.
*/
TRACE_IRQS_OFF
+ IBRS_ENTER
movq %rsp, %rdi
call do_int80_syscall_32
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -202,7 +202,7 @@
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
#define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */
#define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enabled */
-/* FREE! ( 7*32+12) */
+#define X86_FEATURE_KERNEL_IBRS ( 7*32+12) /* "" Set/clear IBRS on kernel entry/exit */
/* FREE! ( 7*32+13) */
#define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Number */
#define X86_FEATURE_CDP_L2 ( 7*32+15) /* Code and Data Prioritization L2 */
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 14/34] x86/bugs: Optimize SPEC_CTRL MSR writes
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (12 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 13/34] x86/entry: Add kernel IBRS implementation Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 15/34] x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS Greg Kroah-Hartman
` (24 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit c779bc1a9002fa474175b80e72b85c9bf628abb0 upstream.
When changing SPEC_CTRL for user control, the WRMSR can be delayed
until return-to-user when KERNEL_IBRS has been enabled.
This avoids an MSR write during context switch.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 2 +-
arch/x86/kernel/cpu/bugs.c | 18 ++++++++++++------
arch/x86/kernel/process.c | 2 +-
3 files changed, 14 insertions(+), 8 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -307,7 +307,7 @@ static inline void indirect_branch_predi
/* The Intel SPEC CTRL MSR base value cache */
extern u64 x86_spec_ctrl_base;
-extern void write_spec_ctrl_current(u64 val);
+extern void write_spec_ctrl_current(u64 val, bool force);
/*
* With retpoline, we must use IBRS to restrict branch prediction
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -61,13 +61,19 @@ static DEFINE_MUTEX(spec_ctrl_mutex);
* Keep track of the SPEC_CTRL MSR value for the current task, which may differ
* from x86_spec_ctrl_base due to STIBP/SSB in __speculation_ctrl_update().
*/
-void write_spec_ctrl_current(u64 val)
+void write_spec_ctrl_current(u64 val, bool force)
{
if (this_cpu_read(x86_spec_ctrl_current) == val)
return;
this_cpu_write(x86_spec_ctrl_current, val);
- wrmsrl(MSR_IA32_SPEC_CTRL, val);
+
+ /*
+ * When KERNEL_IBRS this MSR is written on return-to-user, unless
+ * forced the update can be delayed until that time.
+ */
+ if (force || !cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS))
+ wrmsrl(MSR_IA32_SPEC_CTRL, val);
}
/*
@@ -1195,7 +1201,7 @@ static void __init spectre_v2_select_mit
if (spectre_v2_in_eibrs_mode(mode)) {
/* Force it so VMEXIT will restore correctly */
x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
- write_spec_ctrl_current(x86_spec_ctrl_base);
+ write_spec_ctrl_current(x86_spec_ctrl_base, true);
}
switch (mode) {
@@ -1250,7 +1256,7 @@ static void __init spectre_v2_select_mit
static void update_stibp_msr(void * __unused)
{
- write_spec_ctrl_current(x86_spec_ctrl_base);
+ write_spec_ctrl_current(x86_spec_ctrl_base, true);
}
/* Update x86_spec_ctrl_base in case SMT state changed. */
@@ -1493,7 +1499,7 @@ static enum ssb_mitigation __init __ssb_
x86_amd_ssb_disable();
} else {
x86_spec_ctrl_base |= SPEC_CTRL_SSBD;
- write_spec_ctrl_current(x86_spec_ctrl_base);
+ write_spec_ctrl_current(x86_spec_ctrl_base, true);
}
}
@@ -1698,7 +1704,7 @@ int arch_prctl_spec_ctrl_get(struct task
void x86_spec_ctrl_setup_ap(void)
{
if (boot_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
- write_spec_ctrl_current(x86_spec_ctrl_base);
+ write_spec_ctrl_current(x86_spec_ctrl_base, true);
if (ssb_mode == SPEC_STORE_BYPASS_DISABLE)
x86_amd_ssb_disable();
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -434,7 +434,7 @@ static __always_inline void __speculatio
}
if (updmsr)
- write_spec_ctrl_current(msr);
+ write_spec_ctrl_current(msr, false);
}
static unsigned long speculation_ctrl_update_tif(struct task_struct *tsk)
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 15/34] x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (13 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 14/34] x86/bugs: Optimize SPEC_CTRL MSR writes Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 16/34] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() Greg Kroah-Hartman
` (23 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Pawan Gupta, Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
commit 7c693f54c873691a4b7da05c7e0f74e67745d144 upstream.
Extend spectre_v2= boot option with Kernel IBRS.
[jpoimboe: no STIBP with IBRS]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/admin-guide/kernel-parameters.txt | 1
arch/x86/include/asm/nospec-branch.h | 1
arch/x86/kernel/cpu/bugs.c | 66 ++++++++++++++++++------
3 files changed, 54 insertions(+), 14 deletions(-)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4389,6 +4389,7 @@
eibrs - enhanced IBRS
eibrs,retpoline - enhanced IBRS + Retpolines
eibrs,lfence - enhanced IBRS + LFENCE
+ ibrs - use IBRS to protect kernel
Not specifying this option is equivalent to
spectre_v2=auto.
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -244,6 +244,7 @@ enum spectre_v2_mitigation {
SPECTRE_V2_EIBRS,
SPECTRE_V2_EIBRS_RETPOLINE,
SPECTRE_V2_EIBRS_LFENCE,
+ SPECTRE_V2_IBRS,
};
/* The indirect branch speculation control variants */
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -877,6 +877,7 @@ enum spectre_v2_mitigation_cmd {
SPECTRE_V2_CMD_EIBRS,
SPECTRE_V2_CMD_EIBRS_RETPOLINE,
SPECTRE_V2_CMD_EIBRS_LFENCE,
+ SPECTRE_V2_CMD_IBRS,
};
enum spectre_v2_user_cmd {
@@ -949,11 +950,12 @@ spectre_v2_parse_user_cmdline(enum spect
return SPECTRE_V2_USER_CMD_AUTO;
}
-static inline bool spectre_v2_in_eibrs_mode(enum spectre_v2_mitigation mode)
+static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode)
{
- return (mode == SPECTRE_V2_EIBRS ||
- mode == SPECTRE_V2_EIBRS_RETPOLINE ||
- mode == SPECTRE_V2_EIBRS_LFENCE);
+ return mode == SPECTRE_V2_IBRS ||
+ mode == SPECTRE_V2_EIBRS ||
+ mode == SPECTRE_V2_EIBRS_RETPOLINE ||
+ mode == SPECTRE_V2_EIBRS_LFENCE;
}
static void __init
@@ -1018,12 +1020,12 @@ spectre_v2_user_select_mitigation(enum s
}
/*
- * If no STIBP, enhanced IBRS is enabled or SMT impossible, STIBP is not
- * required.
+ * If no STIBP, IBRS or enhanced IBRS is enabled, or SMT impossible,
+ * STIBP is not required.
*/
if (!boot_cpu_has(X86_FEATURE_STIBP) ||
!smt_possible ||
- spectre_v2_in_eibrs_mode(spectre_v2_enabled))
+ spectre_v2_in_ibrs_mode(spectre_v2_enabled))
return;
/*
@@ -1048,6 +1050,7 @@ static const char * const spectre_v2_str
[SPECTRE_V2_EIBRS] = "Mitigation: Enhanced IBRS",
[SPECTRE_V2_EIBRS_LFENCE] = "Mitigation: Enhanced IBRS + LFENCE",
[SPECTRE_V2_EIBRS_RETPOLINE] = "Mitigation: Enhanced IBRS + Retpolines",
+ [SPECTRE_V2_IBRS] = "Mitigation: IBRS",
};
static const struct {
@@ -1065,6 +1068,7 @@ static const struct {
{ "eibrs,lfence", SPECTRE_V2_CMD_EIBRS_LFENCE, false },
{ "eibrs,retpoline", SPECTRE_V2_CMD_EIBRS_RETPOLINE, false },
{ "auto", SPECTRE_V2_CMD_AUTO, false },
+ { "ibrs", SPECTRE_V2_CMD_IBRS, false },
};
static void __init spec_v2_print_cond(const char *reason, bool secure)
@@ -1127,6 +1131,24 @@ static enum spectre_v2_mitigation_cmd __
return SPECTRE_V2_CMD_AUTO;
}
+ if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) {
+ pr_err("%s selected but not Intel CPU. Switching to AUTO select\n",
+ mitigation_options[i].option);
+ return SPECTRE_V2_CMD_AUTO;
+ }
+
+ if (cmd == SPECTRE_V2_CMD_IBRS && !boot_cpu_has(X86_FEATURE_IBRS)) {
+ pr_err("%s selected but CPU doesn't have IBRS. Switching to AUTO select\n",
+ mitigation_options[i].option);
+ return SPECTRE_V2_CMD_AUTO;
+ }
+
+ if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_has(X86_FEATURE_XENPV)) {
+ pr_err("%s selected but running as XenPV guest. Switching to AUTO select\n",
+ mitigation_options[i].option);
+ return SPECTRE_V2_CMD_AUTO;
+ }
+
spec_v2_print_cond(mitigation_options[i].option,
mitigation_options[i].secure);
return cmd;
@@ -1166,6 +1188,14 @@ static void __init spectre_v2_select_mit
break;
}
+ if (boot_cpu_has_bug(X86_BUG_RETBLEED) &&
+ retbleed_cmd != RETBLEED_CMD_OFF &&
+ boot_cpu_has(X86_FEATURE_IBRS) &&
+ boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) {
+ mode = SPECTRE_V2_IBRS;
+ break;
+ }
+
mode = spectre_v2_select_retpoline();
break;
@@ -1182,6 +1212,10 @@ static void __init spectre_v2_select_mit
mode = spectre_v2_select_retpoline();
break;
+ case SPECTRE_V2_CMD_IBRS:
+ mode = SPECTRE_V2_IBRS;
+ break;
+
case SPECTRE_V2_CMD_EIBRS:
mode = SPECTRE_V2_EIBRS;
break;
@@ -1198,7 +1232,7 @@ static void __init spectre_v2_select_mit
if (mode == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled())
pr_err(SPECTRE_V2_EIBRS_EBPF_MSG);
- if (spectre_v2_in_eibrs_mode(mode)) {
+ if (spectre_v2_in_ibrs_mode(mode)) {
/* Force it so VMEXIT will restore correctly */
x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
write_spec_ctrl_current(x86_spec_ctrl_base, true);
@@ -1209,6 +1243,10 @@ static void __init spectre_v2_select_mit
case SPECTRE_V2_EIBRS:
break;
+ case SPECTRE_V2_IBRS:
+ setup_force_cpu_cap(X86_FEATURE_KERNEL_IBRS);
+ break;
+
case SPECTRE_V2_LFENCE:
case SPECTRE_V2_EIBRS_LFENCE:
setup_force_cpu_cap(X86_FEATURE_RETPOLINE_LFENCE);
@@ -1235,17 +1273,17 @@ static void __init spectre_v2_select_mit
pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n");
/*
- * Retpoline means the kernel is safe because it has no indirect
- * branches. Enhanced IBRS protects firmware too, so, enable restricted
- * speculation around firmware calls only when Enhanced IBRS isn't
- * supported.
+ * Retpoline protects the kernel, but doesn't protect firmware. IBRS
+ * and Enhanced IBRS protect firmware too, so enable IBRS around
+ * firmware calls only when IBRS / Enhanced IBRS aren't otherwise
+ * enabled.
*
* Use "mode" to check Enhanced IBRS instead of boot_cpu_has(), because
* the user might select retpoline on the kernel command line and if
* the CPU supports Enhanced IBRS, kernel might un-intentionally not
* enable IBRS around firmware calls.
*/
- if (boot_cpu_has(X86_FEATURE_IBRS) && !spectre_v2_in_eibrs_mode(mode)) {
+ if (boot_cpu_has(X86_FEATURE_IBRS) && !spectre_v2_in_ibrs_mode(mode)) {
setup_force_cpu_cap(X86_FEATURE_USE_IBRS_FW);
pr_info("Enabling Restricted Speculation for firmware calls\n");
}
@@ -1939,7 +1977,7 @@ static ssize_t mmio_stale_data_show_stat
static char *stibp_state(void)
{
- if (spectre_v2_in_eibrs_mode(spectre_v2_enabled))
+ if (spectre_v2_in_ibrs_mode(spectre_v2_enabled))
return "";
switch (spectre_v2_user_stibp) {
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 16/34] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation()
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (14 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 15/34] x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 17/34] x86/bugs: Report Intel retbleed vulnerability Greg Kroah-Hartman
` (22 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit 166115c08a9b0b846b783088808a27d739be6e8d upstream.
retbleed will depend on spectre_v2, while spectre_v2_user depends on
retbleed. Break this cycle.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -36,8 +36,9 @@
#include "cpu.h"
static void __init spectre_v1_select_mitigation(void);
-static void __init retbleed_select_mitigation(void);
static void __init spectre_v2_select_mitigation(void);
+static void __init retbleed_select_mitigation(void);
+static void __init spectre_v2_user_select_mitigation(void);
static void __init ssb_select_mitigation(void);
static void __init l1tf_select_mitigation(void);
static void __init mds_select_mitigation(void);
@@ -136,13 +137,19 @@ void __init check_bugs(void)
/* Select the proper CPU mitigations before patching alternatives: */
spectre_v1_select_mitigation();
+ spectre_v2_select_mitigation();
+ /*
+ * retbleed_select_mitigation() relies on the state set by
+ * spectre_v2_select_mitigation(); specifically it wants to know about
+ * spectre_v2=ibrs.
+ */
retbleed_select_mitigation();
/*
- * spectre_v2_select_mitigation() relies on the state set by
+ * spectre_v2_user_select_mitigation() relies on the state set by
* retbleed_select_mitigation(); specifically the STIBP selection is
* forced for UNRET.
*/
- spectre_v2_select_mitigation();
+ spectre_v2_user_select_mitigation();
ssb_select_mitigation();
l1tf_select_mitigation();
md_clear_select_mitigation();
@@ -918,13 +925,15 @@ static void __init spec_v2_user_print_co
pr_info("spectre_v2_user=%s forced on command line.\n", reason);
}
+static __ro_after_init enum spectre_v2_mitigation_cmd spectre_v2_cmd;
+
static enum spectre_v2_user_cmd __init
-spectre_v2_parse_user_cmdline(enum spectre_v2_mitigation_cmd v2_cmd)
+spectre_v2_parse_user_cmdline(void)
{
char arg[20];
int ret, i;
- switch (v2_cmd) {
+ switch (spectre_v2_cmd) {
case SPECTRE_V2_CMD_NONE:
return SPECTRE_V2_USER_CMD_NONE;
case SPECTRE_V2_CMD_FORCE:
@@ -959,7 +968,7 @@ static inline bool spectre_v2_in_ibrs_mo
}
static void __init
-spectre_v2_user_select_mitigation(enum spectre_v2_mitigation_cmd v2_cmd)
+spectre_v2_user_select_mitigation(void)
{
enum spectre_v2_user_mitigation mode = SPECTRE_V2_USER_NONE;
bool smt_possible = IS_ENABLED(CONFIG_SMP);
@@ -972,7 +981,7 @@ spectre_v2_user_select_mitigation(enum s
cpu_smt_control == CPU_SMT_NOT_SUPPORTED)
smt_possible = false;
- cmd = spectre_v2_parse_user_cmdline(v2_cmd);
+ cmd = spectre_v2_parse_user_cmdline();
switch (cmd) {
case SPECTRE_V2_USER_CMD_NONE:
goto set_mode;
@@ -1289,7 +1298,7 @@ static void __init spectre_v2_select_mit
}
/* Set up IBPB and STIBP depending on the general spectre V2 command */
- spectre_v2_user_select_mitigation(cmd);
+ spectre_v2_cmd = cmd;
}
static void update_stibp_msr(void * __unused)
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 17/34] x86/bugs: Report Intel retbleed vulnerability
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (15 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 16/34] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 18/34] intel_idle: Disable IBRS during long idle Greg Kroah-Hartman
` (21 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit 6ad0ad2bf8a67e27d1f9d006a1dabb0e1c360cc3 upstream.
Skylake suffers from RSB underflow speculation issues; report this
vulnerability and it's mitigation (spectre_v2=ibrs).
[jpoimboe: cleanups, eibrs]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[suleiman: different processor names]
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/kernel/cpu/bugs.c | 36 +++++++++++++++++++++++++++++++-----
arch/x86/kernel/cpu/common.c | 24 ++++++++++++------------
3 files changed, 44 insertions(+), 17 deletions(-)
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -73,6 +73,7 @@
#define MSR_IA32_ARCH_CAPABILITIES 0x0000010a
#define ARCH_CAP_RDCL_NO BIT(0) /* Not susceptible to Meltdown */
#define ARCH_CAP_IBRS_ALL BIT(1) /* Enhanced IBRS support */
+#define ARCH_CAP_RSBA BIT(2) /* RET may use alternative branch predictors */
#define ARCH_CAP_SKIP_VMENTRY_L1DFLUSH BIT(3) /* Skip L1D flush on vmentry */
#define ARCH_CAP_SSB_NO BIT(4) /*
* Not susceptible to Speculative Store Bypass
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -743,11 +743,16 @@ static int __init nospectre_v1_cmdline(c
}
early_param("nospectre_v1", nospectre_v1_cmdline);
+static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =
+ SPECTRE_V2_NONE;
+
#undef pr_fmt
#define pr_fmt(fmt) "RETBleed: " fmt
enum retbleed_mitigation {
RETBLEED_MITIGATION_NONE,
+ RETBLEED_MITIGATION_IBRS,
+ RETBLEED_MITIGATION_EIBRS,
};
enum retbleed_mitigation_cmd {
@@ -757,6 +762,8 @@ enum retbleed_mitigation_cmd {
const char * const retbleed_strings[] = {
[RETBLEED_MITIGATION_NONE] = "Vulnerable",
+ [RETBLEED_MITIGATION_IBRS] = "Mitigation: IBRS",
+ [RETBLEED_MITIGATION_EIBRS] = "Mitigation: Enhanced IBRS",
};
static enum retbleed_mitigation retbleed_mitigation __ro_after_init =
@@ -782,6 +789,7 @@ early_param("retbleed", retbleed_parse_c
#define RETBLEED_UNTRAIN_MSG "WARNING: BTB untrained return thunk mitigation is only effective on AMD/Hygon!\n"
#define RETBLEED_COMPILER_MSG "WARNING: kernel not compiled with RETPOLINE or -mfunction-return capable compiler!\n"
+#define RETBLEED_INTEL_MSG "WARNING: Spectre v2 mitigation leaves CPU vulnerable to RETBleed attacks, data leaks possible!\n"
static void __init retbleed_select_mitigation(void)
{
@@ -794,8 +802,10 @@ static void __init retbleed_select_mitig
case RETBLEED_CMD_AUTO:
default:
- if (!boot_cpu_has_bug(X86_BUG_RETBLEED))
- break;
+ /*
+ * The Intel mitigation (IBRS) was already selected in
+ * spectre_v2_select_mitigation().
+ */
break;
}
@@ -805,15 +815,31 @@ static void __init retbleed_select_mitig
break;
}
+ /*
+ * Let IBRS trump all on Intel without affecting the effects of the
+ * retbleed= cmdline option.
+ */
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) {
+ switch (spectre_v2_enabled) {
+ case SPECTRE_V2_IBRS:
+ retbleed_mitigation = RETBLEED_MITIGATION_IBRS;
+ break;
+ case SPECTRE_V2_EIBRS:
+ case SPECTRE_V2_EIBRS_RETPOLINE:
+ case SPECTRE_V2_EIBRS_LFENCE:
+ retbleed_mitigation = RETBLEED_MITIGATION_EIBRS;
+ break;
+ default:
+ pr_err(RETBLEED_INTEL_MSG);
+ }
+ }
+
pr_info("%s\n", retbleed_strings[retbleed_mitigation]);
}
#undef pr_fmt
#define pr_fmt(fmt) "Spectre V2 : " fmt
-static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =
- SPECTRE_V2_NONE;
-
static enum spectre_v2_user_mitigation spectre_v2_user_stibp __ro_after_init =
SPECTRE_V2_USER_NONE;
static enum spectre_v2_user_mitigation spectre_v2_user_ibpb __ro_after_init =
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1048,24 +1048,24 @@ static const struct x86_cpu_id cpu_vuln_
VULNBL_INTEL_STEPPINGS(BROADWELL_GT3E, X86_STEPPING_ANY, SRBDS),
VULNBL_INTEL_STEPPINGS(BROADWELL_X, X86_STEPPING_ANY, MMIO),
VULNBL_INTEL_STEPPINGS(BROADWELL_CORE, X86_STEPPING_ANY, SRBDS),
- VULNBL_INTEL_STEPPINGS(SKYLAKE_MOBILE, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE_MOBILE, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO | RETBLEED),
VULNBL_INTEL_STEPPINGS(SKYLAKE_MOBILE, X86_STEPPING_ANY, SRBDS),
VULNBL_INTEL_STEPPINGS(SKYLAKE_X, BIT(3) | BIT(4) | BIT(6) |
- BIT(7) | BIT(0xB), MMIO),
- VULNBL_INTEL_STEPPINGS(SKYLAKE_DESKTOP, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO),
+ BIT(7) | BIT(0xB), MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE_DESKTOP, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO | RETBLEED),
VULNBL_INTEL_STEPPINGS(SKYLAKE_DESKTOP, X86_STEPPING_ANY, SRBDS),
- VULNBL_INTEL_STEPPINGS(KABYLAKE_MOBILE, X86_STEPPINGS(0x9, 0xC), SRBDS | MMIO),
+ VULNBL_INTEL_STEPPINGS(KABYLAKE_MOBILE, X86_STEPPINGS(0x9, 0xC), SRBDS | MMIO | RETBLEED),
VULNBL_INTEL_STEPPINGS(KABYLAKE_MOBILE, X86_STEPPINGS(0x0, 0x8), SRBDS),
- VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPINGS(0x9, 0xD), SRBDS | MMIO),
+ VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPINGS(0x9, 0xD), SRBDS | MMIO | RETBLEED),
VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPINGS(0x0, 0x8), SRBDS),
- VULNBL_INTEL_STEPPINGS(ICELAKE_MOBILE, X86_STEPPINGS(0x5, 0x5), MMIO | MMIO_SBDS),
+ VULNBL_INTEL_STEPPINGS(ICELAKE_MOBILE, X86_STEPPINGS(0x5, 0x5), MMIO | MMIO_SBDS | RETBLEED),
VULNBL_INTEL_STEPPINGS(ICELAKE_XEON_D, X86_STEPPINGS(0x1, 0x1), MMIO),
VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPINGS(0x4, 0x6), MMIO),
- VULNBL_INTEL_STEPPINGS(COMETLAKE, BIT(2) | BIT(3) | BIT(5), MMIO | MMIO_SBDS),
- VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
- VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO),
- VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
- VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPINGS(0x1, 0x1), MMIO),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE, BIT(2) | BIT(3) | BIT(5), MMIO | MMIO_SBDS | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPINGS(0x1, 0x1), MMIO | RETBLEED),
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_X, X86_STEPPING_ANY, MMIO),
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO | MMIO_SBDS),
@@ -1178,7 +1178,7 @@ static void __init cpu_set_bug_bits(stru
setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN);
}
- if (cpu_matches(cpu_vuln_blacklist, RETBLEED))
+ if ((cpu_matches(cpu_vuln_blacklist, RETBLEED) || (ia32_cap & ARCH_CAP_RSBA)))
setup_force_cpu_bug(X86_BUG_RETBLEED);
if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 18/34] intel_idle: Disable IBRS during long idle
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (16 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 17/34] x86/bugs: Report Intel retbleed vulnerability Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 19/34] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool Greg Kroah-Hartman
` (20 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Tim Chen, Peter Zijlstra (Intel),
Borislav Petkov, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit bf5835bcdb9635c97f85120dba9bfa21e111130f upstream.
Having IBRS enabled while the SMT sibling is idle unnecessarily slows
down the running sibling. OTOH, disabling IBRS around idle takes two
MSR writes, which will increase the idle latency.
Therefore, only disable IBRS around deeper idle states. Shallow idle
states are bounded by the tick in duration, since NOHZ is not allowed
for them by virtue of their short target residency.
Only do this for mwait-driven idle, since that keeps interrupts disabled
across idle, which makes disabling IBRS vs IRQ-entry a non-issue.
Note: C6 is a random threshold, most importantly C1 probably shouldn't
disable IBRS, benchmarking needed.
Suggested-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
[cascardo: no CPUIDLE_FLAG_IRQ_ENABLE]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[cascardo: context adjustments]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 1
arch/x86/kernel/cpu/bugs.c | 6 ++++
drivers/idle/intel_idle.c | 43 ++++++++++++++++++++++++++++++-----
3 files changed, 44 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -309,6 +309,7 @@ static inline void indirect_branch_predi
/* The Intel SPEC CTRL MSR base value cache */
extern u64 x86_spec_ctrl_base;
extern void write_spec_ctrl_current(u64 val, bool force);
+extern u64 spec_ctrl_current(void);
/*
* With retpoline, we must use IBRS to restrict branch prediction
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -77,6 +77,12 @@ void write_spec_ctrl_current(u64 val, bo
wrmsrl(MSR_IA32_SPEC_CTRL, val);
}
+u64 spec_ctrl_current(void)
+{
+ return this_cpu_read(x86_spec_ctrl_current);
+}
+EXPORT_SYMBOL_GPL(spec_ctrl_current);
+
/*
* The vendor and possibly platform specific bits which can be modified in
* x86_spec_ctrl_base.
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -58,11 +58,13 @@
#include <linux/tick.h>
#include <trace/events/power.h>
#include <linux/sched.h>
+#include <linux/sched/smt.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/moduleparam.h>
#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>
+#include <asm/nospec-branch.h>
#include <asm/mwait.h>
#include <asm/msr.h>
@@ -110,6 +112,12 @@ static struct cpuidle_state *cpuidle_sta
#define CPUIDLE_FLAG_TLB_FLUSHED 0x10000
/*
+ * Disable IBRS across idle (when KERNEL_IBRS), is exclusive vs IRQ_ENABLE
+ * above.
+ */
+#define CPUIDLE_FLAG_IBRS BIT(16)
+
+/*
* MWAIT takes an 8-bit "hint" in EAX "suggesting"
* the C-state (top nibble) and sub-state (bottom nibble)
* 0x00 means "MWAIT(C1)", 0x10 means "MWAIT(C2)" etc.
@@ -119,6 +127,24 @@ static struct cpuidle_state *cpuidle_sta
#define flg2MWAIT(flags) (((flags) >> 24) & 0xFF)
#define MWAIT2flg(eax) ((eax & 0xFF) << 24)
+static __cpuidle int intel_idle_ibrs(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv, int index)
+{
+ bool smt_active = sched_smt_active();
+ u64 spec_ctrl = spec_ctrl_current();
+ int ret;
+
+ if (smt_active)
+ wrmsrl(MSR_IA32_SPEC_CTRL, 0);
+
+ ret = intel_idle(dev, drv, index);
+
+ if (smt_active)
+ wrmsrl(MSR_IA32_SPEC_CTRL, spec_ctrl);
+
+ return ret;
+}
+
/*
* States are indexed by the cstate number,
* which is also the index into the MWAIT hint array.
@@ -617,7 +643,7 @@ static struct cpuidle_state skl_cstates[
{
.name = "C6",
.desc = "MWAIT 0x20",
- .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
+ .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED | CPUIDLE_FLAG_IBRS,
.exit_latency = 85,
.target_residency = 200,
.enter = &intel_idle,
@@ -625,7 +651,7 @@ static struct cpuidle_state skl_cstates[
{
.name = "C7s",
.desc = "MWAIT 0x33",
- .flags = MWAIT2flg(0x33) | CPUIDLE_FLAG_TLB_FLUSHED,
+ .flags = MWAIT2flg(0x33) | CPUIDLE_FLAG_TLB_FLUSHED | CPUIDLE_FLAG_IBRS,
.exit_latency = 124,
.target_residency = 800,
.enter = &intel_idle,
@@ -633,7 +659,7 @@ static struct cpuidle_state skl_cstates[
{
.name = "C8",
.desc = "MWAIT 0x40",
- .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
+ .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED | CPUIDLE_FLAG_IBRS,
.exit_latency = 200,
.target_residency = 800,
.enter = &intel_idle,
@@ -641,7 +667,7 @@ static struct cpuidle_state skl_cstates[
{
.name = "C9",
.desc = "MWAIT 0x50",
- .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
+ .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED | CPUIDLE_FLAG_IBRS,
.exit_latency = 480,
.target_residency = 5000,
.enter = &intel_idle,
@@ -649,7 +675,7 @@ static struct cpuidle_state skl_cstates[
{
.name = "C10",
.desc = "MWAIT 0x60",
- .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
+ .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED | CPUIDLE_FLAG_IBRS,
.exit_latency = 890,
.target_residency = 5000,
.enter = &intel_idle,
@@ -678,7 +704,7 @@ static struct cpuidle_state skx_cstates[
{
.name = "C6",
.desc = "MWAIT 0x20",
- .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
+ .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED | CPUIDLE_FLAG_IBRS,
.exit_latency = 133,
.target_residency = 600,
.enter = &intel_idle,
@@ -1384,6 +1410,11 @@ static void __init intel_idle_cpuidle_dr
drv->states[drv->state_count] = /* structure copy */
cpuidle_state_table[cstate];
+ if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) &&
+ cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_IBRS) {
+ drv->states[drv->state_count].enter = intel_idle_ibrs;
+ }
+
drv->state_count += 1;
}
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 19/34] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (17 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 18/34] intel_idle: Disable IBRS during long idle Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 20/34] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n Greg Kroah-Hartman
` (19 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Alexandre Chartre, Josh Poimboeuf, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit 089dd8e53126ebaf506e2dc0bf89d652c36bfc12 upstream.
Change FILL_RETURN_BUFFER so that objtool groks it and can generate
correct ORC unwind information.
- Since ORC is alternative invariant; that is, all alternatives
should have the same ORC entries, the __FILL_RETURN_BUFFER body
can not be part of an alternative.
Therefore, move it out of the alternative and keep the alternative
as a sort of jump_label around it.
- Use the ANNOTATE_INTRA_FUNCTION_CALL annotation to white-list
these 'funny' call instructions to nowhere.
- Use UNWIND_HINT_EMPTY to 'fill' the speculation traps, otherwise
objtool will consider them unreachable.
- Move the RSP adjustment into the loop, such that the loop has a
deterministic stack layout.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200428191700.032079304@infradead.org
[cascardo: fixup because of backport of ba6e31af2be96c4d0536f2152ed6f7b6c11bca47 ("x86/speculation: Add LFENCE to RSB fill sequence")]
[cascardo: no intra-function call validation support]
[cascardo: avoid UNWIND_HINT_EMPTY because of svm]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -4,11 +4,13 @@
#define _ASM_X86_NOSPEC_BRANCH_H_
#include <linux/static_key.h>
+#include <linux/frame.h>
#include <asm/alternative.h>
#include <asm/alternative-asm.h>
#include <asm/cpufeatures.h>
#include <asm/msr-index.h>
+#include <asm/unwind_hints.h>
/*
* Fill the CPU return stack buffer.
@@ -51,9 +53,9 @@
lfence; \
jmp 775b; \
774: \
+ add $(BITS_PER_LONG/8) * 2, sp; \
dec reg; \
jnz 771b; \
- add $(BITS_PER_LONG/8) * nr, sp; \
/* barrier for jnz misprediction */ \
lfence;
#else
@@ -158,10 +160,8 @@
*/
.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
#ifdef CONFIG_RETPOLINE
- ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE "jmp .Lskip_rsb_\@", \
- __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \
- \ftr
+ ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr
+ __FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)
.Lskip_rsb_\@:
#endif
.endm
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 20/34] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (18 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 19/34] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 21/34] x86/speculation: Fix firmware entry SPEC_CTRL handling Greg Kroah-Hartman
` (18 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Josh Poimboeuf,
Peter Zijlstra (Intel),
Borislav Petkov, Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit b2620facef4889fefcbf2e87284f34dcd4189bce upstream.
If a kernel is built with CONFIG_RETPOLINE=n, but the user still wants
to mitigate Spectre v2 using IBRS or eIBRS, the RSB filling will be
silently disabled.
There's nothing retpoline-specific about RSB buffer filling. Remove the
CONFIG_RETPOLINE guards around it.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/entry/entry_32.S | 2 --
arch/x86/entry/entry_64.S | 2 --
arch/x86/include/asm/nospec-branch.h | 2 --
3 files changed, 6 deletions(-)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -643,7 +643,6 @@ ENTRY(__switch_to_asm)
movl %ebx, PER_CPU_VAR(stack_canary)+stack_canary_offset
#endif
-#ifdef CONFIG_RETPOLINE
/*
* When switching from a shallower to a deeper call stack
* the RSB may either underflow or use entries populated
@@ -652,7 +651,6 @@ ENTRY(__switch_to_asm)
* speculative execution to prevent attack.
*/
FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
-#endif
/* restore callee-saved registers */
popfl
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -367,7 +367,6 @@ ENTRY(__switch_to_asm)
movq %rbx, PER_CPU_VAR(irq_stack_union)+stack_canary_offset
#endif
-#ifdef CONFIG_RETPOLINE
/*
* When switching from a shallower to a deeper call stack
* the RSB may either underflow or use entries populated
@@ -376,7 +375,6 @@ ENTRY(__switch_to_asm)
* speculative execution to prevent attack.
*/
FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
-#endif
/* restore callee-saved registers */
popfq
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -159,11 +159,9 @@
* monstrosity above, manually.
*/
.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
-#ifdef CONFIG_RETPOLINE
ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr
__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)
.Lskip_rsb_\@:
-#endif
.endm
#else /* __ASSEMBLY__ */
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 21/34] x86/speculation: Fix firmware entry SPEC_CTRL handling
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (19 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 20/34] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 22/34] x86/speculation: Fix SPEC_CTRL write on SMT state change Greg Kroah-Hartman
` (17 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Josh Poimboeuf,
Peter Zijlstra (Intel),
Borislav Petkov, Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit e6aa13622ea8283cc699cac5d018cc40a2ba2010 upstream.
The firmware entry code may accidentally clear STIBP or SSBD. Fix that.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -317,18 +317,16 @@ extern u64 spec_ctrl_current(void);
*/
#define firmware_restrict_branch_speculation_start() \
do { \
- u64 val = x86_spec_ctrl_base | SPEC_CTRL_IBRS; \
- \
preempt_disable(); \
- alternative_msr_write(MSR_IA32_SPEC_CTRL, val, \
+ alternative_msr_write(MSR_IA32_SPEC_CTRL, \
+ spec_ctrl_current() | SPEC_CTRL_IBRS, \
X86_FEATURE_USE_IBRS_FW); \
} while (0)
#define firmware_restrict_branch_speculation_end() \
do { \
- u64 val = x86_spec_ctrl_base; \
- \
- alternative_msr_write(MSR_IA32_SPEC_CTRL, val, \
+ alternative_msr_write(MSR_IA32_SPEC_CTRL, \
+ spec_ctrl_current(), \
X86_FEATURE_USE_IBRS_FW); \
preempt_enable(); \
} while (0)
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 22/34] x86/speculation: Fix SPEC_CTRL write on SMT state change
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (20 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 21/34] x86/speculation: Fix firmware entry SPEC_CTRL handling Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 23/34] x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit Greg Kroah-Hartman
` (16 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Josh Poimboeuf,
Peter Zijlstra (Intel),
Borislav Petkov, Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit 56aa4d221f1ee2c3a49b45b800778ec6e0ab73c5 upstream.
If the SMT state changes, SSBD might get accidentally disabled. Fix
that.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1335,7 +1335,8 @@ static void __init spectre_v2_select_mit
static void update_stibp_msr(void * __unused)
{
- write_spec_ctrl_current(x86_spec_ctrl_base, true);
+ u64 val = spec_ctrl_current() | (x86_spec_ctrl_base & SPEC_CTRL_STIBP);
+ write_spec_ctrl_current(val, true);
}
/* Update x86_spec_ctrl_base in case SMT state changed. */
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 23/34] x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (21 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 22/34] x86/speculation: Fix SPEC_CTRL write on SMT state change Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 24/34] x86/speculation: Remove x86_spec_ctrl_mask Greg Kroah-Hartman
` (15 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Josh Poimboeuf,
Peter Zijlstra (Intel),
Borislav Petkov, Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit bbb69e8bee1bd882784947095ffb2bfe0f7c9470 upstream.
There's no need to recalculate the host value for every entry/exit.
Just use the cached value in spec_ctrl_current().
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 12 +-----------
1 file changed, 1 insertion(+), 11 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -198,7 +198,7 @@ void __init check_bugs(void)
void
x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)
{
- u64 msrval, guestval, hostval = x86_spec_ctrl_base;
+ u64 msrval, guestval, hostval = spec_ctrl_current();
struct thread_info *ti = current_thread_info();
/* Is MSR_SPEC_CTRL implemented ? */
@@ -211,15 +211,6 @@ x86_virt_spec_ctrl(u64 guest_spec_ctrl,
guestval = hostval & ~x86_spec_ctrl_mask;
guestval |= guest_spec_ctrl & x86_spec_ctrl_mask;
- /* SSBD controlled in MSR_SPEC_CTRL */
- if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
- static_cpu_has(X86_FEATURE_AMD_SSBD))
- hostval |= ssbd_tif_to_spec_ctrl(ti->flags);
-
- /* Conditional STIBP enabled? */
- if (static_branch_unlikely(&switch_to_cond_stibp))
- hostval |= stibp_tif_to_spec_ctrl(ti->flags);
-
if (hostval != guestval) {
msrval = setguest ? guestval : hostval;
wrmsrl(MSR_IA32_SPEC_CTRL, msrval);
@@ -1274,7 +1265,6 @@ static void __init spectre_v2_select_mit
pr_err(SPECTRE_V2_EIBRS_EBPF_MSG);
if (spectre_v2_in_ibrs_mode(mode)) {
- /* Force it so VMEXIT will restore correctly */
x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
write_spec_ctrl_current(x86_spec_ctrl_base, true);
}
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 24/34] x86/speculation: Remove x86_spec_ctrl_mask
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (22 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 23/34] x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 25/34] KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS Greg Kroah-Hartman
` (14 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Josh Poimboeuf, Borislav Petkov,
Paolo Bonzini, Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit acac5e98ef8d638a411cfa2ee676c87e1973f126 upstream.
This mask has been made redundant by kvm_spec_ctrl_test_value(). And it
doesn't even work when MSR interception is disabled, as the guest can
just write to SPEC_CTRL directly.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 31 +------------------------------
1 file changed, 1 insertion(+), 30 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -84,12 +84,6 @@ u64 spec_ctrl_current(void)
EXPORT_SYMBOL_GPL(spec_ctrl_current);
/*
- * The vendor and possibly platform specific bits which can be modified in
- * x86_spec_ctrl_base.
- */
-static u64 __ro_after_init x86_spec_ctrl_mask = SPEC_CTRL_IBRS;
-
-/*
* AMD specific MSR info for Speculative Store Bypass control.
* x86_amd_ls_cfg_ssbd_mask is initialized in identify_boot_cpu().
*/
@@ -137,10 +131,6 @@ void __init check_bugs(void)
if (boot_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
rdmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
- /* Allow STIBP in MSR_SPEC_CTRL if supported */
- if (boot_cpu_has(X86_FEATURE_STIBP))
- x86_spec_ctrl_mask |= SPEC_CTRL_STIBP;
-
/* Select the proper CPU mitigations before patching alternatives: */
spectre_v1_select_mitigation();
spectre_v2_select_mitigation();
@@ -198,19 +188,10 @@ void __init check_bugs(void)
void
x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)
{
- u64 msrval, guestval, hostval = spec_ctrl_current();
+ u64 msrval, guestval = guest_spec_ctrl, hostval = spec_ctrl_current();
struct thread_info *ti = current_thread_info();
- /* Is MSR_SPEC_CTRL implemented ? */
if (static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL)) {
- /*
- * Restrict guest_spec_ctrl to supported values. Clear the
- * modifiable bits in the host base value and or the
- * modifiable bits from the guest value.
- */
- guestval = hostval & ~x86_spec_ctrl_mask;
- guestval |= guest_spec_ctrl & x86_spec_ctrl_mask;
-
if (hostval != guestval) {
msrval = setguest ? guestval : hostval;
wrmsrl(MSR_IA32_SPEC_CTRL, msrval);
@@ -1543,16 +1524,6 @@ static enum ssb_mitigation __init __ssb_
}
/*
- * If SSBD is controlled by the SPEC_CTRL MSR, then set the proper
- * bit in the mask to allow guests to use the mitigation even in the
- * case where the host does not enable it.
- */
- if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
- static_cpu_has(X86_FEATURE_AMD_SSBD)) {
- x86_spec_ctrl_mask |= SPEC_CTRL_SSBD;
- }
-
- /*
* We have three CPU feature flags that are in play here:
* - X86_BUG_SPEC_STORE_BYPASS - CPU is susceptible.
* - X86_FEATURE_SSBD - CPU is able to turn off speculative store bypass
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 25/34] KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (23 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 24/34] x86/speculation: Remove x86_spec_ctrl_mask Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 26/34] KVM: VMX: Fix IBRS handling after vmexit Greg Kroah-Hartman
` (13 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Josh Poimboeuf,
Peter Zijlstra (Intel),
Borislav Petkov, Thadeu Lima de Souza Cascardo,
Suraj Jitindar Singh, Suleiman Souhlal
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit fc02735b14fff8c6678b521d324ade27b1a3d4cf upstream.
On eIBRS systems, the returns in the vmexit return path from
__vmx_vcpu_run() to vmx_vcpu_run() are exposed to RSB poisoning attacks.
Fix that by moving the post-vmexit spec_ctrl handling to immediately
after the vmexit.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[ bp: Adjust for the fact that vmexit is in inline assembly ]
Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 3 +-
arch/x86/kernel/cpu/bugs.c | 4 +++
arch/x86/kvm/vmx.c | 46 ++++++++++++++++++++++++++++++-----
3 files changed, 46 insertions(+), 7 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -271,7 +271,7 @@ extern char __indirect_thunk_end[];
* retpoline and IBRS mitigations for Spectre v2 need this; only on future
* CPUs with IBRS_ALL *might* it be avoided.
*/
-static inline void vmexit_fill_RSB(void)
+static __always_inline void vmexit_fill_RSB(void)
{
#ifdef CONFIG_RETPOLINE
unsigned long loops;
@@ -306,6 +306,7 @@ static inline void indirect_branch_predi
/* The Intel SPEC CTRL MSR base value cache */
extern u64 x86_spec_ctrl_base;
+extern u64 x86_spec_ctrl_current;
extern void write_spec_ctrl_current(u64 val, bool force);
extern u64 spec_ctrl_current(void);
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -185,6 +185,10 @@ void __init check_bugs(void)
#endif
}
+/*
+ * NOTE: For VMX, this function is not called in the vmexit path.
+ * It uses vmx_spec_ctrl_restore_host() instead.
+ */
void
x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)
{
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10760,10 +10760,31 @@ static void vmx_update_hv_timer(struct k
vmx->loaded_vmcs->hv_timer_armed = false;
}
+u64 __always_inline vmx_spec_ctrl_restore_host(struct vcpu_vmx *vmx)
+{
+ u64 guestval, hostval = this_cpu_read(x86_spec_ctrl_current);
+
+ if (!cpu_feature_enabled(X86_FEATURE_MSR_SPEC_CTRL))
+ return 0;
+
+ guestval = __rdmsr(MSR_IA32_SPEC_CTRL);
+
+ /*
+ * If the guest/host SPEC_CTRL values differ, restore the host value.
+ */
+ if (guestval != hostval)
+ native_wrmsrl(MSR_IA32_SPEC_CTRL, hostval);
+
+ barrier_nospec();
+
+ return guestval;
+}
+
static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long cr3, cr4, evmcs_rsp;
+ u64 spec_ctrl;
/* Record the guest's net vcpu time for enforced NMI injections. */
if (unlikely(!enable_vnmi &&
@@ -10989,6 +11010,24 @@ static void __noclone vmx_vcpu_run(struc
#endif
);
+ /*
+ * IMPORTANT: RSB filling and SPEC_CTRL handling must be done before
+ * the first unbalanced RET after vmexit!
+ *
+ * For retpoline, RSB filling is needed to prevent poisoned RSB entries
+ * and (in some cases) RSB underflow.
+ *
+ * eIBRS has its own protection against poisoned RSB, so it doesn't
+ * need the RSB filling sequence. But it does need to be enabled
+ * before the first unbalanced RET.
+ *
+ * So no RETs before vmx_spec_ctrl_restore_host() below.
+ */
+ vmexit_fill_RSB();
+
+ /* Save this for below */
+ spec_ctrl = vmx_spec_ctrl_restore_host(vmx);
+
vmx_enable_fb_clear(vmx);
/*
@@ -11007,12 +11046,7 @@ static void __noclone vmx_vcpu_run(struc
* save it.
*/
if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL)))
- vmx->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL);
-
- x86_spec_ctrl_restore_host(vmx->spec_ctrl, 0);
-
- /* Eliminate branch target predictions from guest mode */
- vmexit_fill_RSB();
+ vmx->spec_ctrl = spec_ctrl;
/* All fields are clean at this point */
if (static_branch_unlikely(&enable_evmcs))
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 26/34] KVM: VMX: Fix IBRS handling after vmexit
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (24 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 25/34] KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 27/34] x86/speculation: Fill RSB on vmexit for IBRS Greg Kroah-Hartman
` (12 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Josh Poimboeuf,
Peter Zijlstra (Intel),
Borislav Petkov, Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit bea7e31a5caccb6fe8ed989c065072354f0ecb52 upstream.
For legacy IBRS to work, the IBRS bit needs to be always re-written
after vmexit, even if it's already on.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/vmx.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10770,9 +10770,13 @@ u64 __always_inline vmx_spec_ctrl_restor
guestval = __rdmsr(MSR_IA32_SPEC_CTRL);
/*
- * If the guest/host SPEC_CTRL values differ, restore the host value.
+ *
+ * For legacy IBRS, the IBRS bit always needs to be written after
+ * transitioning from a less privileged predictor mode, regardless of
+ * whether the guest/host values differ.
*/
- if (guestval != hostval)
+ if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) ||
+ guestval != hostval)
native_wrmsrl(MSR_IA32_SPEC_CTRL, hostval);
barrier_nospec();
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 27/34] x86/speculation: Fill RSB on vmexit for IBRS
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (25 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 26/34] KVM: VMX: Fix IBRS handling after vmexit Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 28/34] x86/common: Stamp out the stepping madness Greg Kroah-Hartman
` (11 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Josh Poimboeuf,
Peter Zijlstra (Intel),
Borislav Petkov, Thadeu Lima de Souza Cascardo,
Suraj Jitindar Singh, Suleiman Souhlal
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit 9756bba28470722dacb79ffce554336dd1f6a6cd upstream.
Prevent RSB underflow/poisoning attacks with RSB. While at it, add a
bunch of comments to attempt to document the current state of tribal
knowledge about RSB attacks and what exactly is being mitigated.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[ bp: Adjust for the fact that vmexit is in inline assembly ]
Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpufeatures.h | 2 -
arch/x86/include/asm/nospec-branch.h | 2 -
arch/x86/kernel/cpu/bugs.c | 63 ++++++++++++++++++++++++++++++++---
arch/x86/kvm/vmx.c | 4 +-
4 files changed, 62 insertions(+), 9 deletions(-)
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -203,7 +203,7 @@
#define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */
#define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enabled */
#define X86_FEATURE_KERNEL_IBRS ( 7*32+12) /* "" Set/clear IBRS on kernel entry/exit */
-/* FREE! ( 7*32+13) */
+#define X86_FEATURE_RSB_VMEXIT ( 7*32+13) /* "" Fill RSB on VM-Exit */
#define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Number */
#define X86_FEATURE_CDP_L2 ( 7*32+15) /* Code and Data Prioritization L2 */
#define X86_FEATURE_MSR_SPEC_CTRL ( 7*32+16) /* "" MSR SPEC_CTRL is implemented */
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -279,7 +279,7 @@ static __always_inline void vmexit_fill_
asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE
ALTERNATIVE("jmp 910f",
__stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1)),
- X86_FEATURE_RETPOLINE)
+ X86_FEATURE_RSB_VMEXIT)
"910:"
: "=r" (loops), ASM_CALL_CONSTRAINT
: : "memory" );
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1278,17 +1278,70 @@ static void __init spectre_v2_select_mit
pr_info("%s\n", spectre_v2_strings[mode]);
/*
- * If spectre v2 protection has been enabled, unconditionally fill
- * RSB during a context switch; this protects against two independent
- * issues:
+ * If Spectre v2 protection has been enabled, fill the RSB during a
+ * context switch. In general there are two types of RSB attacks
+ * across context switches, for which the CALLs/RETs may be unbalanced.
*
- * - RSB underflow (and switch to BTB) on Skylake+
- * - SpectreRSB variant of spectre v2 on X86_BUG_SPECTRE_V2 CPUs
+ * 1) RSB underflow
+ *
+ * Some Intel parts have "bottomless RSB". When the RSB is empty,
+ * speculated return targets may come from the branch predictor,
+ * which could have a user-poisoned BTB or BHB entry.
+ *
+ * AMD has it even worse: *all* returns are speculated from the BTB,
+ * regardless of the state of the RSB.
+ *
+ * When IBRS or eIBRS is enabled, the "user -> kernel" attack
+ * scenario is mitigated by the IBRS branch prediction isolation
+ * properties, so the RSB buffer filling wouldn't be necessary to
+ * protect against this type of attack.
+ *
+ * The "user -> user" attack scenario is mitigated by RSB filling.
+ *
+ * 2) Poisoned RSB entry
+ *
+ * If the 'next' in-kernel return stack is shorter than 'prev',
+ * 'next' could be tricked into speculating with a user-poisoned RSB
+ * entry.
+ *
+ * The "user -> kernel" attack scenario is mitigated by SMEP and
+ * eIBRS.
+ *
+ * The "user -> user" scenario, also known as SpectreBHB, requires
+ * RSB clearing.
+ *
+ * So to mitigate all cases, unconditionally fill RSB on context
+ * switches.
+ *
+ * FIXME: Is this pointless for retbleed-affected AMD?
*/
setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW);
pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n");
/*
+ * Similar to context switches, there are two types of RSB attacks
+ * after vmexit:
+ *
+ * 1) RSB underflow
+ *
+ * 2) Poisoned RSB entry
+ *
+ * When retpoline is enabled, both are mitigated by filling/clearing
+ * the RSB.
+ *
+ * When IBRS is enabled, while #1 would be mitigated by the IBRS branch
+ * prediction isolation protections, RSB still needs to be cleared
+ * because of #2. Note that SMEP provides no protection here, unlike
+ * user-space-poisoned RSB entries.
+ *
+ * eIBRS, on the other hand, has RSB-poisoning protections, so it
+ * doesn't need RSB clearing after vmexit.
+ */
+ if (boot_cpu_has(X86_FEATURE_RETPOLINE) ||
+ boot_cpu_has(X86_FEATURE_KERNEL_IBRS))
+ setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT);
+
+ /*
* Retpoline protects the kernel, but doesn't protect firmware. IBRS
* and Enhanced IBRS protect firmware too, so enable IBRS around
* firmware calls only when IBRS / Enhanced IBRS aren't otherwise
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11018,8 +11018,8 @@ static void __noclone vmx_vcpu_run(struc
* IMPORTANT: RSB filling and SPEC_CTRL handling must be done before
* the first unbalanced RET after vmexit!
*
- * For retpoline, RSB filling is needed to prevent poisoned RSB entries
- * and (in some cases) RSB underflow.
+ * For retpoline or IBRS, RSB filling is needed to prevent poisoned RSB
+ * entries and (in some cases) RSB underflow.
*
* eIBRS has its own protection against poisoned RSB, so it doesn't
* need the RSB filling sequence. But it does need to be enabled
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 28/34] x86/common: Stamp out the stepping madness
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (26 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 27/34] x86/speculation: Fill RSB on vmexit for IBRS Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 29/34] x86/cpu/amd: Enumerate BTC_NO Greg Kroah-Hartman
` (10 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Peter Zijlstra (Intel),
Borislav Petkov, Dave Hansen, Thadeu Lima de Souza Cascardo,
Suleiman Souhlal
From: Peter Zijlstra <peterz@infradead.org>
commit 7a05bc95ed1c5a59e47aaade9fb4083c27de9e62 upstream.
The whole MMIO/RETBLEED enumeration went overboard on steppings. Get
rid of all that and simply use ANY.
If a future stepping of these models would not be affected, it had
better set the relevant ARCH_CAP_$FOO_NO bit in
IA32_ARCH_CAPABILITIES.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/common.c | 38 ++++++++++++++++----------------------
1 file changed, 16 insertions(+), 22 deletions(-)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1043,32 +1043,26 @@ static const struct x86_cpu_id cpu_vuln_
VULNBL_INTEL_STEPPINGS(HASWELL_CORE, X86_STEPPING_ANY, SRBDS),
VULNBL_INTEL_STEPPINGS(HASWELL_ULT, X86_STEPPING_ANY, SRBDS),
VULNBL_INTEL_STEPPINGS(HASWELL_GT3E, X86_STEPPING_ANY, SRBDS),
- VULNBL_INTEL_STEPPINGS(HASWELL_X, BIT(2) | BIT(4), MMIO),
- VULNBL_INTEL_STEPPINGS(BROADWELL_XEON_D,X86_STEPPINGS(0x3, 0x5), MMIO),
+ VULNBL_INTEL_STEPPINGS(HASWELL_X, X86_STEPPING_ANY, MMIO),
+ VULNBL_INTEL_STEPPINGS(BROADWELL_XEON_D,X86_STEPPING_ANY, MMIO),
VULNBL_INTEL_STEPPINGS(BROADWELL_GT3E, X86_STEPPING_ANY, SRBDS),
VULNBL_INTEL_STEPPINGS(BROADWELL_X, X86_STEPPING_ANY, MMIO),
VULNBL_INTEL_STEPPINGS(BROADWELL_CORE, X86_STEPPING_ANY, SRBDS),
- VULNBL_INTEL_STEPPINGS(SKYLAKE_MOBILE, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO | RETBLEED),
- VULNBL_INTEL_STEPPINGS(SKYLAKE_MOBILE, X86_STEPPING_ANY, SRBDS),
- VULNBL_INTEL_STEPPINGS(SKYLAKE_X, BIT(3) | BIT(4) | BIT(6) |
- BIT(7) | BIT(0xB), MMIO | RETBLEED),
- VULNBL_INTEL_STEPPINGS(SKYLAKE_DESKTOP, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO | RETBLEED),
- VULNBL_INTEL_STEPPINGS(SKYLAKE_DESKTOP, X86_STEPPING_ANY, SRBDS),
- VULNBL_INTEL_STEPPINGS(KABYLAKE_MOBILE, X86_STEPPINGS(0x9, 0xC), SRBDS | MMIO | RETBLEED),
- VULNBL_INTEL_STEPPINGS(KABYLAKE_MOBILE, X86_STEPPINGS(0x0, 0x8), SRBDS),
- VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPINGS(0x9, 0xD), SRBDS | MMIO | RETBLEED),
- VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPINGS(0x0, 0x8), SRBDS),
- VULNBL_INTEL_STEPPINGS(ICELAKE_MOBILE, X86_STEPPINGS(0x5, 0x5), MMIO | MMIO_SBDS | RETBLEED),
- VULNBL_INTEL_STEPPINGS(ICELAKE_XEON_D, X86_STEPPINGS(0x1, 0x1), MMIO),
- VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPINGS(0x4, 0x6), MMIO),
- VULNBL_INTEL_STEPPINGS(COMETLAKE, BIT(2) | BIT(3) | BIT(5), MMIO | MMIO_SBDS | RETBLEED),
- VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS | RETBLEED),
- VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO | RETBLEED),
- VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS | RETBLEED),
- VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPINGS(0x1, 0x1), MMIO | RETBLEED),
- VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE_MOBILE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE_X, X86_STEPPING_ANY, MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE_DESKTOP, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(KABYLAKE_MOBILE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(ICELAKE_MOBILE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(ICELAKE_XEON_D, X86_STEPPING_ANY, MMIO),
+ VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPING_ANY, MMIO),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPING_ANY, MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPING_ANY, MMIO | MMIO_SBDS),
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_X, X86_STEPPING_ANY, MMIO),
- VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO | MMIO_SBDS),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS),
VULNBL_AMD(0x15, RETBLEED),
VULNBL_AMD(0x16, RETBLEED),
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 29/34] x86/cpu/amd: Enumerate BTC_NO
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (27 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 28/34] x86/common: Stamp out the stepping madness Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 30/34] x86/bugs: Add Cannon lake to RETBleed affected CPU list Greg Kroah-Hartman
` (9 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Andrew Cooper, Borislav Petkov,
Thadeu Lima de Souza Cascardo, Suraj Jitindar Singh,
Suleiman Souhlal
From: Andrew Cooper <andrew.cooper3@citrix.com>
commit 26aae8ccbc1972233afd08fb3f368947c0314265 upstream.
BTC_NO indicates that hardware is not susceptible to Branch Type Confusion.
Zen3 CPUs don't suffer BTC.
Hypervisors are expected to synthesise BTC_NO when it is appropriate
given the migration pool, to prevent kernels using heuristics.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[ bp: Adjust context ]
Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kernel/cpu/amd.c | 21 +++++++++++++++------
arch/x86/kernel/cpu/common.c | 6 ++++--
3 files changed, 20 insertions(+), 8 deletions(-)
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -303,6 +303,7 @@
#define X86_FEATURE_AMD_SSBD (13*32+24) /* "" Speculative Store Bypass Disable */
#define X86_FEATURE_VIRT_SSBD (13*32+25) /* Virtualized Speculative Store Bypass Disable */
#define X86_FEATURE_AMD_SSB_NO (13*32+26) /* "" Speculative Store Bypass is fixed in hardware. */
+#define X86_FEATURE_BTC_NO (13*32+29) /* "" Not vulnerable to Branch Type Confusion */
/* Thermal and Power Management Leaf, CPUID level 0x00000006 (EAX), word 14 */
#define X86_FEATURE_DTHERM (14*32+ 0) /* Digital Thermal Sensor */
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -885,12 +885,21 @@ static void init_amd_zn(struct cpuinfo_x
{
set_cpu_cap(c, X86_FEATURE_ZEN);
- /*
- * Fix erratum 1076: CPB feature bit not being set in CPUID.
- * Always set it, except when running under a hypervisor.
- */
- if (!cpu_has(c, X86_FEATURE_HYPERVISOR) && !cpu_has(c, X86_FEATURE_CPB))
- set_cpu_cap(c, X86_FEATURE_CPB);
+ /* Fix up CPUID bits, but only if not virtualised. */
+ if (!cpu_has(c, X86_FEATURE_HYPERVISOR)) {
+
+ /* Erratum 1076: CPB feature bit not being set in CPUID. */
+ if (!cpu_has(c, X86_FEATURE_CPB))
+ set_cpu_cap(c, X86_FEATURE_CPB);
+
+ /*
+ * Zen3 (Fam19 model < 0x10) parts are not susceptible to
+ * Branch Type Confusion, but predate the allocation of the
+ * BTC_NO bit.
+ */
+ if (c->x86 == 0x19 && !cpu_has(c, X86_FEATURE_BTC_NO))
+ set_cpu_cap(c, X86_FEATURE_BTC_NO);
+ }
}
static void init_amd(struct cpuinfo_x86 *c)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1172,8 +1172,10 @@ static void __init cpu_set_bug_bits(stru
setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN);
}
- if ((cpu_matches(cpu_vuln_blacklist, RETBLEED) || (ia32_cap & ARCH_CAP_RSBA)))
- setup_force_cpu_bug(X86_BUG_RETBLEED);
+ if (!cpu_has(c, X86_FEATURE_BTC_NO)) {
+ if (cpu_matches(cpu_vuln_blacklist, RETBLEED) || (ia32_cap & ARCH_CAP_RSBA))
+ setup_force_cpu_bug(X86_BUG_RETBLEED);
+ }
if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
return;
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 30/34] x86/bugs: Add Cannon lake to RETBleed affected CPU list
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (28 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 29/34] x86/cpu/amd: Enumerate BTC_NO Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 31/34] x86/speculation: Disable RRSBA behavior Greg Kroah-Hartman
` (8 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Pawan Gupta, Borislav Petkov,
Thadeu Lima de Souza Cascardo, Suraj Jitindar Singh,
Suleiman Souhlal
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
commit f54d45372c6ac9c993451de5e51312485f7d10bc upstream.
Cannon lake is also affected by RETBleed, add it to the list.
Fixes: 6ad0ad2bf8a6 ("x86/bugs: Report Intel retbleed vulnerability")
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
[ bp: Adjust cpu model name CANNONLAKE_L -> CANNONLAKE_MOBILE ]
Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/common.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1053,6 +1053,7 @@ static const struct x86_cpu_id cpu_vuln_
VULNBL_INTEL_STEPPINGS(SKYLAKE_DESKTOP, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
VULNBL_INTEL_STEPPINGS(KABYLAKE_MOBILE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED),
+ VULNBL_INTEL_STEPPINGS(CANNONLAKE_MOBILE,X86_STEPPING_ANY, RETBLEED),
VULNBL_INTEL_STEPPINGS(ICELAKE_MOBILE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
VULNBL_INTEL_STEPPINGS(ICELAKE_XEON_D, X86_STEPPING_ANY, MMIO),
VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPING_ANY, MMIO),
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 31/34] x86/speculation: Disable RRSBA behavior
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (29 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 30/34] x86/bugs: Add Cannon lake to RETBleed affected CPU list Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 32/34] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current Greg Kroah-Hartman
` (7 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Pawan Gupta, Borislav Petkov,
Ben Hutchings, Samuel Mendoza-Jonas, Suleiman Souhlal
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
commit 4ad3278df6fe2b0852b00d5757fc2ccd8e92c26e upstream.
Some Intel processors may use alternate predictors for RETs on
RSB-underflow. This condition may be vulnerable to Branch History
Injection (BHI) and intramode-BTI.
Kernel earlier added spectre_v2 mitigation modes (eIBRS+Retpolines,
eIBRS+LFENCE, Retpolines) which protect indirect CALLs and JMPs against
such attacks. However, on RSB-underflow, RET target prediction may
fallback to alternate predictors. As a result, RET's predicted target
may get influenced by branch history.
A new MSR_IA32_SPEC_CTRL bit (RRSBA_DIS_S) controls this fallback
behavior when in kernel mode. When set, RETs will not take predictions
from alternate predictors, hence mitigating RETs as well. Support for
this is enumerated by CPUID.7.2.EDX[RRSBA_CTRL] (bit2).
For spectre v2 mitigation, when a user selects a mitigation that
protects indirect CALLs and JMPs against BHI and intramode-BTI, set
RRSBA_DIS_S also to protect RETs for RSB-underflow case.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
[bwh: Backported to 5.15: adjust context in scattered.c]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[sam: Fixed for missing X86_FEATURE_ENTRY_IBPB context]
Signed-off-by: Samuel Mendoza-Jonas <samjonas@amazon.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpufeatures.h | 2 +-
arch/x86/include/asm/msr-index.h | 9 +++++++++
arch/x86/kernel/cpu/bugs.c | 26 ++++++++++++++++++++++++++
arch/x86/kernel/cpu/scattered.c | 1 +
4 files changed, 37 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -288,7 +288,7 @@
/* FREE! (11*32+ 8) */
/* FREE! (11*32+ 9) */
/* FREE! (11*32+10) */
-/* FREE! (11*32+11) */
+#define X86_FEATURE_RRSBA_CTRL (11*32+11) /* "" RET prediction control */
#define X86_FEATURE_RETPOLINE (11*32+12) /* "" Generic Retpoline mitigation for Spectre variant 2 */
#define X86_FEATURE_RETPOLINE_LFENCE (11*32+13) /* "" Use LFENCE for Spectre variant 2 */
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -47,6 +47,8 @@
#define SPEC_CTRL_STIBP BIT(SPEC_CTRL_STIBP_SHIFT) /* STIBP mask */
#define SPEC_CTRL_SSBD_SHIFT 2 /* Speculative Store Bypass Disable bit */
#define SPEC_CTRL_SSBD BIT(SPEC_CTRL_SSBD_SHIFT) /* Speculative Store Bypass Disable */
+#define SPEC_CTRL_RRSBA_DIS_S_SHIFT 6 /* Disable RRSBA behavior */
+#define SPEC_CTRL_RRSBA_DIS_S BIT(SPEC_CTRL_RRSBA_DIS_S_SHIFT)
#define MSR_IA32_PRED_CMD 0x00000049 /* Prediction Command */
#define PRED_CMD_IBPB BIT(0) /* Indirect Branch Prediction Barrier */
@@ -121,6 +123,13 @@
* bit available to control VERW
* behavior.
*/
+#define ARCH_CAP_RRSBA BIT(19) /*
+ * Indicates RET may use predictors
+ * other than the RSB. With eIBRS
+ * enabled predictions in kernel mode
+ * are restricted to targets in
+ * kernel.
+ */
#define MSR_IA32_FLUSH_CMD 0x0000010b
#define L1D_FLUSH BIT(0) /*
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1181,6 +1181,22 @@ static enum spectre_v2_mitigation __init
return SPECTRE_V2_RETPOLINE;
}
+/* Disable in-kernel use of non-RSB RET predictors */
+static void __init spec_ctrl_disable_kernel_rrsba(void)
+{
+ u64 ia32_cap;
+
+ if (!boot_cpu_has(X86_FEATURE_RRSBA_CTRL))
+ return;
+
+ ia32_cap = x86_read_arch_cap_msr();
+
+ if (ia32_cap & ARCH_CAP_RRSBA) {
+ x86_spec_ctrl_base |= SPEC_CTRL_RRSBA_DIS_S;
+ write_spec_ctrl_current(x86_spec_ctrl_base, true);
+ }
+}
+
static void __init spectre_v2_select_mitigation(void)
{
enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
@@ -1274,6 +1290,16 @@ static void __init spectre_v2_select_mit
break;
}
+ /*
+ * Disable alternate RSB predictions in kernel when indirect CALLs and
+ * JMPs gets protection against BHI and Intramode-BTI, but RET
+ * prediction from a non-RSB predictor is still a risk.
+ */
+ if (mode == SPECTRE_V2_EIBRS_LFENCE ||
+ mode == SPECTRE_V2_EIBRS_RETPOLINE ||
+ mode == SPECTRE_V2_RETPOLINE)
+ spec_ctrl_disable_kernel_rrsba();
+
spectre_v2_enabled = mode;
pr_info("%s\n", spectre_v2_strings[mode]);
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -21,6 +21,7 @@ struct cpuid_bit {
static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_APERFMPERF, CPUID_ECX, 0, 0x00000006, 0 },
{ X86_FEATURE_EPB, CPUID_ECX, 3, 0x00000006, 0 },
+ { X86_FEATURE_RRSBA_CTRL, CPUID_EDX, 2, 0x00000007, 2 },
{ X86_FEATURE_CQM_LLC, CPUID_EDX, 1, 0x0000000f, 0 },
{ X86_FEATURE_CQM_OCCUP_LLC, CPUID_EDX, 0, 0x0000000f, 1 },
{ X86_FEATURE_CQM_MBM_TOTAL, CPUID_EDX, 1, 0x0000000f, 1 },
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 32/34] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (30 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 31/34] x86/speculation: Disable RRSBA behavior Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 33/34] x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts Greg Kroah-Hartman
` (6 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, kernel test robot,
Nathan Chancellor, Linus Torvalds, Suleiman Souhlal
From: Nathan Chancellor <nathan@kernel.org>
commit db886979683a8360ced9b24ab1125ad0c4d2cf76 upstream.
Clang warns:
arch/x86/kernel/cpu/bugs.c:58:21: error: section attribute is specified on redeclared variable [-Werror,-Wsection]
DEFINE_PER_CPU(u64, x86_spec_ctrl_current);
^
arch/x86/include/asm/nospec-branch.h:283:12: note: previous declaration is here
extern u64 x86_spec_ctrl_current;
^
1 error generated.
The declaration should be using DECLARE_PER_CPU instead so all
attributes stay in sync.
Cc: stable@vger.kernel.org
Fixes: fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -11,6 +11,7 @@
#include <asm/cpufeatures.h>
#include <asm/msr-index.h>
#include <asm/unwind_hints.h>
+#include <asm/percpu.h>
/*
* Fill the CPU return stack buffer.
@@ -306,7 +307,7 @@ static inline void indirect_branch_predi
/* The Intel SPEC CTRL MSR base value cache */
extern u64 x86_spec_ctrl_base;
-extern u64 x86_spec_ctrl_current;
+DECLARE_PER_CPU(u64, x86_spec_ctrl_current);
extern void write_spec_ctrl_current(u64 val, bool force);
extern u64 spec_ctrl_current(void);
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 33/34] x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (31 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 32/34] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 34/34] x86/speculation: Add RSB VM Exit protections Greg Kroah-Hartman
` (5 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Pawan Gupta, Peter Zijlstra (Intel),
Thadeu Lima de Souza Cascardo, Suleiman Souhlal
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
commit eb23b5ef9131e6d65011de349a4d25ef1b3d4314 upstream.
IBRS mitigation for spectre_v2 forces write to MSR_IA32_SPEC_CTRL at
every kernel entry/exit. On Enhanced IBRS parts setting
MSR_IA32_SPEC_CTRL[IBRS] only once at boot is sufficient. MSR writes at
every kernel entry/exit incur unnecessary performance loss.
When Enhanced IBRS feature is present, print a warning about this
unnecessary performance loss.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/2a5eaf54583c2bfe0edc4fea64006656256cca17.1657814857.git.pawan.kumar.gupta@linux.intel.com
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 3 +++
1 file changed, 3 insertions(+)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -851,6 +851,7 @@ static inline const char *spectre_v2_mod
#define SPECTRE_V2_LFENCE_MSG "WARNING: LFENCE mitigation is not recommended for this CPU, data leaks possible!\n"
#define SPECTRE_V2_EIBRS_EBPF_MSG "WARNING: Unprivileged eBPF is enabled with eIBRS on, data leaks possible via Spectre v2 BHB attacks!\n"
#define SPECTRE_V2_EIBRS_LFENCE_EBPF_SMT_MSG "WARNING: Unprivileged eBPF is enabled with eIBRS+LFENCE mitigation and SMT, data leaks possible via Spectre v2 BHB attacks!\n"
+#define SPECTRE_V2_IBRS_PERF_MSG "WARNING: IBRS mitigation selected on Enhanced IBRS CPU, this may cause unnecessary performance loss\n"
#ifdef CONFIG_BPF_SYSCALL
void unpriv_ebpf_notify(int new_state)
@@ -1277,6 +1278,8 @@ static void __init spectre_v2_select_mit
case SPECTRE_V2_IBRS:
setup_force_cpu_cap(X86_FEATURE_KERNEL_IBRS);
+ if (boot_cpu_has(X86_FEATURE_IBRS_ENHANCED))
+ pr_warn(SPECTRE_V2_IBRS_PERF_MSG);
break;
case SPECTRE_V2_LFENCE:
^ permalink raw reply [flat|nested] 41+ messages in thread* [PATCH 4.19 34/34] x86/speculation: Add RSB VM Exit protections
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (32 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 33/34] x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts Greg Kroah-Hartman
@ 2022-11-21 12:43 ` Greg Kroah-Hartman
2022-11-21 18:47 ` [PATCH 4.19 00/34] 4.19.266-rc1 review Shuah Khan
` (4 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Greg Kroah-Hartman @ 2022-11-21 12:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Daniel Sneddon, Pawan Gupta,
Borislav Petkov, Suraj Jitindar Singh, Suleiman Souhlal
From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
commit 2b1299322016731d56807aa49254a5ea3080b6b3 upstream.
tl;dr: The Enhanced IBRS mitigation for Spectre v2 does not work as
documented for RET instructions after VM exits. Mitigate it with a new
one-entry RSB stuffing mechanism and a new LFENCE.
== Background ==
Indirect Branch Restricted Speculation (IBRS) was designed to help
mitigate Branch Target Injection and Speculative Store Bypass, i.e.
Spectre, attacks. IBRS prevents software run in less privileged modes
from affecting branch prediction in more privileged modes. IBRS requires
the MSR to be written on every privilege level change.
To overcome some of the performance issues of IBRS, Enhanced IBRS was
introduced. eIBRS is an "always on" IBRS, in other words, just turn
it on once instead of writing the MSR on every privilege level change.
When eIBRS is enabled, more privileged modes should be protected from
less privileged modes, including protecting VMMs from guests.
== Problem ==
Here's a simplification of how guests are run on Linux' KVM:
void run_kvm_guest(void)
{
// Prepare to run guest
VMRESUME();
// Clean up after guest runs
}
The execution flow for that would look something like this to the
processor:
1. Host-side: call run_kvm_guest()
2. Host-side: VMRESUME
3. Guest runs, does "CALL guest_function"
4. VM exit, host runs again
5. Host might make some "cleanup" function calls
6. Host-side: RET from run_kvm_guest()
Now, when back on the host, there are a couple of possible scenarios of
post-guest activity the host needs to do before executing host code:
* on pre-eIBRS hardware (legacy IBRS, or nothing at all), the RSB is not
touched and Linux has to do a 32-entry stuffing.
* on eIBRS hardware, VM exit with IBRS enabled, or restoring the host
IBRS=1 shortly after VM exit, has a documented side effect of flushing
the RSB except in this PBRSB situation where the software needs to stuff
the last RSB entry "by hand".
IOW, with eIBRS supported, host RET instructions should no longer be
influenced by guest behavior after the host retires a single CALL
instruction.
However, if the RET instructions are "unbalanced" with CALLs after a VM
exit as is the RET in #6, it might speculatively use the address for the
instruction after the CALL in #3 as an RSB prediction. This is a problem
since the (untrusted) guest controls this address.
Balanced CALL/RET instruction pairs such as in step #5 are not affected.
== Solution ==
The PBRSB issue affects a wide variety of Intel processors which
support eIBRS. But not all of them need mitigation. Today,
X86_FEATURE_RSB_VMEXIT triggers an RSB filling sequence that mitigates
PBRSB. Systems setting RSB_VMEXIT need no further mitigation - i.e.,
eIBRS systems which enable legacy IBRS explicitly.
However, such systems (X86_FEATURE_IBRS_ENHANCED) do not set RSB_VMEXIT
and most of them need a new mitigation.
Therefore, introduce a new feature flag X86_FEATURE_RSB_VMEXIT_LITE
which triggers a lighter-weight PBRSB mitigation versus RSB_VMEXIT.
The lighter-weight mitigation performs a CALL instruction which is
immediately followed by a speculative execution barrier (INT3). This
steers speculative execution to the barrier -- just like a retpoline
-- which ensures that speculation can never reach an unbalanced RET.
Then, ensure this CALL is retired before continuing execution with an
LFENCE.
In other words, the window of exposure is opened at VM exit where RET
behavior is troublesome. While the window is open, force RSB predictions
sampling for RET targets to a dead end at the INT3. Close the window
with the LFENCE.
There is a subset of eIBRS systems which are not vulnerable to PBRSB.
Add these systems to the cpu_vuln_whitelist[] as NO_EIBRS_PBRSB.
Future systems that aren't vulnerable will set ARCH_CAP_PBRSB_NO.
[ bp: Massage, incorporate review comments from Andy Cooper. ]
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Co-developed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
[ bp: Adjust patch to account for kvm entry being in c ]
Signed-off-by: Suraj Jitindar Singh <surajjs@amazon.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/admin-guide/hw-vuln/spectre.rst | 8 ++
arch/x86/include/asm/cpufeatures.h | 2
arch/x86/include/asm/msr-index.h | 4 +
arch/x86/include/asm/nospec-branch.h | 15 +++-
arch/x86/kernel/cpu/bugs.c | 87 +++++++++++++++++++-------
arch/x86/kernel/cpu/common.c | 12 ++-
arch/x86/kvm/vmx.c | 4 -
tools/arch/x86/include/asm/cpufeatures.h | 1
8 files changed, 103 insertions(+), 30 deletions(-)
--- a/Documentation/admin-guide/hw-vuln/spectre.rst
+++ b/Documentation/admin-guide/hw-vuln/spectre.rst
@@ -422,6 +422,14 @@ The possible values in this file are:
'RSB filling' Protection of RSB on context switch enabled
============= ===========================================
+ - EIBRS Post-barrier Return Stack Buffer (PBRSB) protection status:
+
+ =========================== =======================================================
+ 'PBRSB-eIBRS: SW sequence' CPU is affected and protection of RSB on VMEXIT enabled
+ 'PBRSB-eIBRS: Vulnerable' CPU is vulnerable
+ 'PBRSB-eIBRS: Not affected' CPU is not affected by PBRSB
+ =========================== =======================================================
+
Full mitigation might require a microcode update from the CPU
vendor. When the necessary microcode is not available, the kernel will
report vulnerability.
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -291,6 +291,7 @@
#define X86_FEATURE_RRSBA_CTRL (11*32+11) /* "" RET prediction control */
#define X86_FEATURE_RETPOLINE (11*32+12) /* "" Generic Retpoline mitigation for Spectre variant 2 */
#define X86_FEATURE_RETPOLINE_LFENCE (11*32+13) /* "" Use LFENCE for Spectre variant 2 */
+#define X86_FEATURE_RSB_VMEXIT_LITE (11*32+17) /* "" Fill RSB on VM exit when EIBRS is enabled */
/* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */
#define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */
@@ -406,5 +407,6 @@
#define X86_BUG_MMIO_STALE_DATA X86_BUG(25) /* CPU is affected by Processor MMIO Stale Data vulnerabilities */
#define X86_BUG_MMIO_UNKNOWN X86_BUG(26) /* CPU is too old and its MMIO Stale Data status is unknown */
#define X86_BUG_RETBLEED X86_BUG(27) /* CPU is affected by RETBleed */
+#define X86_BUG_EIBRS_PBRSB X86_BUG(28) /* EIBRS is vulnerable to Post Barrier RSB Predictions */
#endif /* _ASM_X86_CPUFEATURES_H */
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -130,6 +130,10 @@
* are restricted to targets in
* kernel.
*/
+#define ARCH_CAP_PBRSB_NO BIT(24) /*
+ * Not susceptible to Post-Barrier
+ * Return Stack Buffer Predictions.
+ */
#define MSR_IA32_FLUSH_CMD 0x0000010b
#define L1D_FLUSH BIT(0) /*
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -73,6 +73,13 @@
add $(BITS_PER_LONG/8) * nr, sp;
#endif
+#define ISSUE_UNBALANCED_RET_GUARD(sp) \
+ call 992f; \
+ int3; \
+992: \
+ add $(BITS_PER_LONG/8), sp; \
+ lfence;
+
#ifdef __ASSEMBLY__
/*
@@ -278,9 +285,11 @@ static __always_inline void vmexit_fill_
unsigned long loops;
asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE("jmp 910f",
- __stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1)),
- X86_FEATURE_RSB_VMEXIT)
+ ALTERNATIVE_2("jmp 910f", "", X86_FEATURE_RSB_VMEXIT,
+ "jmp 911f", X86_FEATURE_RSB_VMEXIT_LITE)
+ __stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1))
+ "911:"
+ __stringify(ISSUE_UNBALANCED_RET_GUARD(%1))
"910:"
: "=r" (loops), ASM_CALL_CONSTRAINT
: : "memory" );
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1198,6 +1198,54 @@ static void __init spec_ctrl_disable_ker
}
}
+static void __init spectre_v2_determine_rsb_fill_type_at_vmexit(enum spectre_v2_mitigation mode)
+{
+ /*
+ * Similar to context switches, there are two types of RSB attacks
+ * after VM exit:
+ *
+ * 1) RSB underflow
+ *
+ * 2) Poisoned RSB entry
+ *
+ * When retpoline is enabled, both are mitigated by filling/clearing
+ * the RSB.
+ *
+ * When IBRS is enabled, while #1 would be mitigated by the IBRS branch
+ * prediction isolation protections, RSB still needs to be cleared
+ * because of #2. Note that SMEP provides no protection here, unlike
+ * user-space-poisoned RSB entries.
+ *
+ * eIBRS should protect against RSB poisoning, but if the EIBRS_PBRSB
+ * bug is present then a LITE version of RSB protection is required,
+ * just a single call needs to retire before a RET is executed.
+ */
+ switch (mode) {
+ case SPECTRE_V2_NONE:
+ return;
+
+ case SPECTRE_V2_EIBRS_LFENCE:
+ case SPECTRE_V2_EIBRS:
+ if (boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB) &&
+ (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)) {
+ setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT_LITE);
+ pr_info("Spectre v2 / PBRSB-eIBRS: Retire a single CALL on VMEXIT\n");
+ }
+ return;
+
+ case SPECTRE_V2_EIBRS_RETPOLINE:
+ case SPECTRE_V2_RETPOLINE:
+ case SPECTRE_V2_LFENCE:
+ case SPECTRE_V2_IBRS:
+ setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT);
+ pr_info("Spectre v2 / SpectreRSB : Filling RSB on VMEXIT\n");
+ return;
+ }
+
+ pr_warn_once("Unknown Spectre v2 mode, disabling RSB mitigation at VM exit");
+ dump_stack();
+}
+
static void __init spectre_v2_select_mitigation(void)
{
enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
@@ -1347,28 +1395,7 @@ static void __init spectre_v2_select_mit
setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW);
pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n");
- /*
- * Similar to context switches, there are two types of RSB attacks
- * after vmexit:
- *
- * 1) RSB underflow
- *
- * 2) Poisoned RSB entry
- *
- * When retpoline is enabled, both are mitigated by filling/clearing
- * the RSB.
- *
- * When IBRS is enabled, while #1 would be mitigated by the IBRS branch
- * prediction isolation protections, RSB still needs to be cleared
- * because of #2. Note that SMEP provides no protection here, unlike
- * user-space-poisoned RSB entries.
- *
- * eIBRS, on the other hand, has RSB-poisoning protections, so it
- * doesn't need RSB clearing after vmexit.
- */
- if (boot_cpu_has(X86_FEATURE_RETPOLINE) ||
- boot_cpu_has(X86_FEATURE_KERNEL_IBRS))
- setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT);
+ spectre_v2_determine_rsb_fill_type_at_vmexit(mode);
/*
* Retpoline protects the kernel, but doesn't protect firmware. IBRS
@@ -2096,6 +2123,19 @@ static char *ibpb_state(void)
return "";
}
+static char *pbrsb_eibrs_state(void)
+{
+ if (boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB)) {
+ if (boot_cpu_has(X86_FEATURE_RSB_VMEXIT_LITE) ||
+ boot_cpu_has(X86_FEATURE_RSB_VMEXIT))
+ return ", PBRSB-eIBRS: SW sequence";
+ else
+ return ", PBRSB-eIBRS: Vulnerable";
+ } else {
+ return ", PBRSB-eIBRS: Not affected";
+ }
+}
+
static ssize_t spectre_v2_show_state(char *buf)
{
if (spectre_v2_enabled == SPECTRE_V2_LFENCE)
@@ -2108,12 +2148,13 @@ static ssize_t spectre_v2_show_state(cha
spectre_v2_enabled == SPECTRE_V2_EIBRS_LFENCE)
return sprintf(buf, "Vulnerable: eIBRS+LFENCE with unprivileged eBPF and SMT\n");
- return sprintf(buf, "%s%s%s%s%s%s\n",
+ return sprintf(buf, "%s%s%s%s%s%s%s\n",
spectre_v2_strings[spectre_v2_enabled],
ibpb_state(),
boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
stibp_state(),
boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
+ pbrsb_eibrs_state(),
spectre_v2_module_string());
}
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -955,6 +955,7 @@ static void identify_cpu_without_cpuid(s
#define NO_SWAPGS BIT(6)
#define NO_ITLB_MULTIHIT BIT(7)
#define NO_MMIO BIT(8)
+#define NO_EIBRS_PBRSB BIT(9)
#define VULNWL(_vendor, _family, _model, _whitelist) \
{ X86_VENDOR_##_vendor, _family, _model, X86_FEATURE_ANY, _whitelist }
@@ -996,7 +997,7 @@ static const __initconst struct x86_cpu_
VULNWL_INTEL(ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
VULNWL_INTEL(ATOM_GOLDMONT_X, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
- VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
+ VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO | NO_EIBRS_PBRSB),
/*
* Technically, swapgs isn't serializing on AMD (despite it previously
@@ -1006,7 +1007,9 @@ static const __initconst struct x86_cpu_
* good enough for our purposes.
*/
- VULNWL_INTEL(ATOM_TREMONT_X, NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_TREMONT, NO_EIBRS_PBRSB),
+ VULNWL_INTEL(ATOM_TREMONT_L, NO_EIBRS_PBRSB),
+ VULNWL_INTEL(ATOM_TREMONT_X, NO_ITLB_MULTIHIT | NO_EIBRS_PBRSB),
/* AMD Family 0xf - 0x12 */
VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT | NO_MMIO),
@@ -1178,6 +1181,11 @@ static void __init cpu_set_bug_bits(stru
setup_force_cpu_bug(X86_BUG_RETBLEED);
}
+ if (cpu_has(c, X86_FEATURE_IBRS_ENHANCED) &&
+ !cpu_matches(cpu_vuln_whitelist, NO_EIBRS_PBRSB) &&
+ !(ia32_cap & ARCH_CAP_PBRSB_NO))
+ setup_force_cpu_bug(X86_BUG_EIBRS_PBRSB);
+
if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
return;
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11022,8 +11022,8 @@ static void __noclone vmx_vcpu_run(struc
* entries and (in some cases) RSB underflow.
*
* eIBRS has its own protection against poisoned RSB, so it doesn't
- * need the RSB filling sequence. But it does need to be enabled
- * before the first unbalanced RET.
+ * need the RSB filling sequence. But it does need to be enabled, and a
+ * single call to retire, before the first unbalanced RET.
*
* So no RETs before vmx_spec_ctrl_restore_host() below.
*/
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -271,6 +271,7 @@
/* Intel-defined CPU QoS Sub-leaf, CPUID level 0x0000000F:0 (EDX), word 11 */
#define X86_FEATURE_CQM_LLC (11*32+ 1) /* LLC QoS if 1 */
+#define X86_FEATURE_RSB_VMEXIT_LITE (11*32+17) /* "" Fill RSB on VM-Exit when EIBRS is enabled */
/* Intel-defined CPU QoS Sub-leaf, CPUID level 0x0000000F:1 (EDX), word 12 */
#define X86_FEATURE_CQM_OCCUP_LLC (12*32+ 0) /* LLC occupancy monitoring */
^ permalink raw reply [flat|nested] 41+ messages in thread* Re: [PATCH 4.19 00/34] 4.19.266-rc1 review
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (33 preceding siblings ...)
2022-11-21 12:43 ` [PATCH 4.19 34/34] x86/speculation: Add RSB VM Exit protections Greg Kroah-Hartman
@ 2022-11-21 18:47 ` Shuah Khan
2022-11-21 19:02 ` Pavel Machek
` (3 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Shuah Khan @ 2022-11-21 18:47 UTC (permalink / raw)
To: Greg Kroah-Hartman, stable
Cc: patches, linux-kernel, torvalds, akpm, linux, shuah, patches,
lkft-triage, pavel, jonathanh, f.fainelli, sudipm.mukherjee, srw,
rwarsow, Shuah Khan
On 11/21/22 05:43, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.19.266 release.
> There are 34 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Wed, 23 Nov 2022 12:41:40 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
> https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.19.266-rc1.gz
> or in the git tree and branch at:
> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.19.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
>
Compiled and booted on my test system. No dmesg regressions.
Tested-by: Shuah Khan <skhan@linuxfoundation.org>
thanks,
-- Shuah
^ permalink raw reply [flat|nested] 41+ messages in thread* Re: [PATCH 4.19 00/34] 4.19.266-rc1 review
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (34 preceding siblings ...)
2022-11-21 18:47 ` [PATCH 4.19 00/34] 4.19.266-rc1 review Shuah Khan
@ 2022-11-21 19:02 ` Pavel Machek
2022-11-22 6:29 ` Naresh Kamboju
` (2 subsequent siblings)
38 siblings, 0 replies; 41+ messages in thread
From: Pavel Machek @ 2022-11-21 19:02 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: stable, patches, linux-kernel, torvalds, akpm, linux, shuah,
patches, lkft-triage, pavel, jonathanh, f.fainelli,
sudipm.mukherjee, srw, rwarsow
[-- Attachment #1: Type: text/plain, Size: 1196 bytes --]
Hi!
> This is the start of the stable review cycle for the 4.19.266 release.
> There are 34 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
CIP testing did not find any problems here:
https://gitlab.com/cip-project/cip-testing/linux-stable-rc-ci/-/tree/linux-4.19.y
Tested-by: Pavel Machek (CIP) <pavel@denx.de>
Best regards,
Pavel
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]
^ permalink raw reply [flat|nested] 41+ messages in thread* Re: [PATCH 4.19 00/34] 4.19.266-rc1 review
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (35 preceding siblings ...)
2022-11-21 19:02 ` Pavel Machek
@ 2022-11-22 6:29 ` Naresh Kamboju
2022-11-22 10:16 ` Jon Hunter
2022-11-22 16:58 ` Guenter Roeck
38 siblings, 0 replies; 41+ messages in thread
From: Naresh Kamboju @ 2022-11-22 6:29 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: stable, patches, linux-kernel, torvalds, akpm, linux, shuah,
patches, lkft-triage, pavel, jonathanh, f.fainelli,
sudipm.mukherjee, srw, rwarsow
On Mon, 21 Nov 2022 at 18:14, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> This is the start of the stable review cycle for the 4.19.266 release.
> There are 34 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Wed, 23 Nov 2022 12:41:40 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
> https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.19.266-rc1.gz
> or in the git tree and branch at:
> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.19.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
Results from Linaro’s test farm.
No regressions on arm64, arm, x86_64, and i386.
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
## Build
* kernel: 4.19.266-rc1
* git: https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc
* git branch: linux-4.19.y
* git commit: 002bfba64dfd861e50556a611a3378bdca4ac7b9
* git describe: v4.19.265-35-g002bfba64dfd
* test details:
https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-4.19.y/build/v4.19.265-35-g002bfba64dfd
## Test Regressions (compared to v4.19.265)
## Metric Regressions (compared to v4.19.265)
## Test Fixes (compared to v4.19.265)
## Metric Fixes (compared to v4.19.265)
## Test result summary
total: 91819, pass: 79207, fail: 1418, skip: 10606, xfail: 588
## Build Summary
* arc: 10 total, 10 passed, 0 failed
* arm: 323 total, 318 passed, 5 failed
* arm64: 59 total, 58 passed, 1 failed
* i386: 29 total, 28 passed, 1 failed
* mips: 46 total, 46 passed, 0 failed
* parisc: 12 total, 12 passed, 0 failed
* powerpc: 63 total, 63 passed, 0 failed
* s390: 15 total, 15 passed, 0 failed
* sh: 24 total, 24 passed, 0 failed
* sparc: 12 total, 12 passed, 0 failed
* x86_64: 53 total, 52 passed, 1 failed
## Test suites summary
* boot
* fwts
* igt-gpu-tools
* kselftest-android
* kselftest-arm64
* kselftest-arm64/arm64.btitest.bti_c_func
* kselftest-arm64/arm64.btitest.bti_j_func
* kselftest-arm64/arm64.btitest.bti_jc_func
* kselftest-arm64/arm64.btitest.bti_none_func
* kselftest-arm64/arm64.btitest.nohint_func
* kselftest-arm64/arm64.btitest.paciasp_func
* kselftest-arm64/arm64.nobtitest.bti_c_func
* kselftest-arm64/arm64.nobtitest.bti_j_func
* kselftest-arm64/arm64.nobtitest.bti_jc_func
* kselftest-arm64/arm64.nobtitest.bti_none_func
* kselftest-arm64/arm64.nobtitest.nohint_func
* kselftest-arm64/arm64.nobtitest.paciasp_func
* kselftest-breakpoints
* kselftest-drivers-dma-buf
* kselftest-efivarfs
* kselftest-gpio
* kselftest-intel_pstate
* kselftest-kvm
* kselftest-lib
* kselftest-net
* kselftest-net-forwarding
* kselftest-net-mptcp
* kselftest-netfilter
* kselftest-openat2
* kselftest-seccomp
* kselftest-timens
* kunit
* kvm-unit-tests
* libhugetlbfs
* log-parser-boot
* log-parser-test
* ltp-cap_bounds
* ltp-commands
* ltp-containers
* ltp-controllers
* ltp-cpuhotplug
* ltp-crypto
* ltp-cve
* ltp-dio
* ltp-fcntl-locktests
* ltp-filecaps
* ltp-fs
* ltp-fs_bind
* ltp-fs_perms_simple
* ltp-fsx
* ltp-hugetlb
* ltp-io
* ltp-ipc
* ltp-math
* ltp-mm
* ltp-nptl
* ltp-open-posix-tests
* ltp-pty
* ltp-sched
* ltp-securebits
* ltp-smoke
* ltp-syscalls
* ltp-tracing
* network-basic-tests
* packetdrill
* rcutorture
* v4l2-compliance
* vdso
--
Linaro LKFT
https://lkft.linaro.org
^ permalink raw reply [flat|nested] 41+ messages in thread* Re: [PATCH 4.19 00/34] 4.19.266-rc1 review
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (36 preceding siblings ...)
2022-11-22 6:29 ` Naresh Kamboju
@ 2022-11-22 10:16 ` Jon Hunter
2022-11-22 16:58 ` Guenter Roeck
38 siblings, 0 replies; 41+ messages in thread
From: Jon Hunter @ 2022-11-22 10:16 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Greg Kroah-Hartman, patches, linux-kernel, torvalds, akpm, linux,
shuah, patches, lkft-triage, pavel, jonathanh, f.fainelli,
sudipm.mukherjee, srw, rwarsow, linux-tegra
On Mon, 21 Nov 2022 13:43:22 +0100, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.19.266 release.
> There are 34 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Wed, 23 Nov 2022 12:41:40 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
> https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.19.266-rc1.gz
> or in the git tree and branch at:
> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.19.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
All tests passing for Tegra ...
Test results for stable-v4.19:
10 builds: 10 pass, 0 fail
22 boots: 22 pass, 0 fail
40 tests: 40 pass, 0 fail
Linux version: 4.19.266-rc1-g002bfba64dfd
Boards tested: tegra124-jetson-tk1, tegra186-p2771-0000,
tegra194-p2972-0000, tegra20-ventana,
tegra210-p2371-2180, tegra30-cardhu-a04
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Jon
^ permalink raw reply [flat|nested] 41+ messages in thread* Re: [PATCH 4.19 00/34] 4.19.266-rc1 review
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
` (37 preceding siblings ...)
2022-11-22 10:16 ` Jon Hunter
@ 2022-11-22 16:58 ` Guenter Roeck
38 siblings, 0 replies; 41+ messages in thread
From: Guenter Roeck @ 2022-11-22 16:58 UTC (permalink / raw)
To: Greg Kroah-Hartman, stable
Cc: patches, linux-kernel, torvalds, akpm, shuah, patches,
lkft-triage, pavel, jonathanh, f.fainelli, sudipm.mukherjee, srw,
rwarsow
On 11/21/22 04:43, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.19.266 release.
> There are 34 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Wed, 23 Nov 2022 12:41:40 +0000.
> Anything received after that time might be too late.
>
Build results:
total: 157 pass: 157 fail: 0
Qemu test results:
total: 423 pass: 423 fail: 0
Tested-by: Guenter Roeck <linux@roeck-us.net>
Guenter
^ permalink raw reply [flat|nested] 41+ messages in thread