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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-08 04:21:41 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-08 04:21:41 +0000
commitb488a8b2c3eaf68ad4778dbdc99bdda0b0d1ce6d (patch)
tree9f60f0d41af253fa943e7811f231d36852f10f1e /debian/patches/bugfix/x86/gds/x86-speculation-add-gather-data-sampling-mitigation.patch
parentMerging upstream version 4.19.304. (diff)
downloadlinux-debian.tar.xz
linux-debian.zip
Adding debian version 4.19.304-1.debian/4.19.304-1debian
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'debian/patches/bugfix/x86/gds/x86-speculation-add-gather-data-sampling-mitigation.patch')
-rw-r--r--debian/patches/bugfix/x86/gds/x86-speculation-add-gather-data-sampling-mitigation.patch562
1 files changed, 0 insertions, 562 deletions
diff --git a/debian/patches/bugfix/x86/gds/x86-speculation-add-gather-data-sampling-mitigation.patch b/debian/patches/bugfix/x86/gds/x86-speculation-add-gather-data-sampling-mitigation.patch
deleted file mode 100644
index c426811c6..000000000
--- a/debian/patches/bugfix/x86/gds/x86-speculation-add-gather-data-sampling-mitigation.patch
+++ /dev/null
@@ -1,562 +0,0 @@
-From d63b3f0e819275ee64648eb01330aad3e347d9ba Mon Sep 17 00:00:00 2001
-From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
-Date: Wed, 12 Jul 2023 19:43:11 -0700
-Subject: x86/speculation: Add Gather Data Sampling mitigation
-
-From: Daniel Sneddon <daniel.sneddon@linux.intel.com>
-
-commit 8974eb588283b7d44a7c91fa09fcbaf380339f3a upstream
-
-Gather Data Sampling (GDS) is a hardware vulnerability which allows
-unprivileged speculative access to data which was previously stored in
-vector registers.
-
-Intel processors that support AVX2 and AVX512 have gather instructions
-that fetch non-contiguous data elements from memory. On vulnerable
-hardware, when a gather instruction is transiently executed and
-encounters a fault, stale data from architectural or internal vector
-registers may get transiently stored to the destination vector
-register allowing an attacker to infer the stale data using typical
-side channel techniques like cache timing attacks.
-
-This mitigation is different from many earlier ones for two reasons.
-First, it is enabled by default and a bit must be set to *DISABLE* it.
-This is the opposite of normal mitigation polarity. This means GDS can
-be mitigated simply by updating microcode and leaving the new control
-bit alone.
-
-Second, GDS has a "lock" bit. This lock bit is there because the
-mitigation affects the hardware security features KeyLocker and SGX.
-It needs to be enabled and *STAY* enabled for these features to be
-mitigated against GDS.
-
-The mitigation is enabled in the microcode by default. Disable it by
-setting gather_data_sampling=off or by disabling all mitigations with
-mitigations=off. The mitigation status can be checked by reading:
-
- /sys/devices/system/cpu/vulnerabilities/gather_data_sampling
-
-Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
-Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
-Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
-Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- Documentation/ABI/testing/sysfs-devices-system-cpu | 11 -
- Documentation/admin-guide/hw-vuln/gather_data_sampling.rst | 99 +++++++++
- Documentation/admin-guide/hw-vuln/index.rst | 1
- Documentation/admin-guide/kernel-parameters.txt | 33 ++-
- arch/x86/include/asm/cpufeatures.h | 1
- arch/x86/include/asm/msr-index.h | 11 +
- arch/x86/kernel/cpu/bugs.c | 129 +++++++++++++
- arch/x86/kernel/cpu/common.c | 34 ++-
- arch/x86/kernel/cpu/cpu.h | 1
- drivers/base/cpu.c | 8
- 10 files changed, 305 insertions(+), 23 deletions(-)
- create mode 100644 Documentation/admin-guide/hw-vuln/gather_data_sampling.rst
-
---- a/Documentation/ABI/testing/sysfs-devices-system-cpu
-+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
-@@ -472,16 +472,17 @@ Description: information about CPUs hete
- cpu_capacity: capacity of cpu#.
-
- What: /sys/devices/system/cpu/vulnerabilities
-+ /sys/devices/system/cpu/vulnerabilities/gather_data_sampling
-+ /sys/devices/system/cpu/vulnerabilities/itlb_multihit
-+ /sys/devices/system/cpu/vulnerabilities/l1tf
-+ /sys/devices/system/cpu/vulnerabilities/mds
- /sys/devices/system/cpu/vulnerabilities/meltdown
-+ /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
-+ /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
- /sys/devices/system/cpu/vulnerabilities/spectre_v1
- /sys/devices/system/cpu/vulnerabilities/spectre_v2
-- /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
-- /sys/devices/system/cpu/vulnerabilities/l1tf
-- /sys/devices/system/cpu/vulnerabilities/mds
- /sys/devices/system/cpu/vulnerabilities/srbds
- /sys/devices/system/cpu/vulnerabilities/tsx_async_abort
-- /sys/devices/system/cpu/vulnerabilities/itlb_multihit
-- /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
- Date: January 2018
- Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
- Description: Information about CPU vulnerabilities
---- /dev/null
-+++ b/Documentation/admin-guide/hw-vuln/gather_data_sampling.rst
-@@ -0,0 +1,99 @@
-+.. SPDX-License-Identifier: GPL-2.0
-+
-+GDS - Gather Data Sampling
-+==========================
-+
-+Gather Data Sampling is a hardware vulnerability which allows unprivileged
-+speculative access to data which was previously stored in vector registers.
-+
-+Problem
-+-------
-+When a gather instruction performs loads from memory, different data elements
-+are merged into the destination vector register. However, when a gather
-+instruction that is transiently executed encounters a fault, stale data from
-+architectural or internal vector registers may get transiently forwarded to the
-+destination vector register instead. This will allow a malicious attacker to
-+infer stale data using typical side channel techniques like cache timing
-+attacks. GDS is a purely sampling-based attack.
-+
-+The attacker uses gather instructions to infer the stale vector register data.
-+The victim does not need to do anything special other than use the vector
-+registers. The victim does not need to use gather instructions to be
-+vulnerable.
-+
-+Because the buffers are shared between Hyper-Threads cross Hyper-Thread attacks
-+are possible.
-+
-+Attack scenarios
-+----------------
-+Without mitigation, GDS can infer stale data across virtually all
-+permission boundaries:
-+
-+ Non-enclaves can infer SGX enclave data
-+ Userspace can infer kernel data
-+ Guests can infer data from hosts
-+ Guest can infer guest from other guests
-+ Users can infer data from other users
-+
-+Because of this, it is important to ensure that the mitigation stays enabled in
-+lower-privilege contexts like guests and when running outside SGX enclaves.
-+
-+The hardware enforces the mitigation for SGX. Likewise, VMMs should ensure
-+that guests are not allowed to disable the GDS mitigation. If a host erred and
-+allowed this, a guest could theoretically disable GDS mitigation, mount an
-+attack, and re-enable it.
-+
-+Mitigation mechanism
-+--------------------
-+This issue is mitigated in microcode. The microcode defines the following new
-+bits:
-+
-+ ================================ === ============================
-+ IA32_ARCH_CAPABILITIES[GDS_CTRL] R/O Enumerates GDS vulnerability
-+ and mitigation support.
-+ IA32_ARCH_CAPABILITIES[GDS_NO] R/O Processor is not vulnerable.
-+ IA32_MCU_OPT_CTRL[GDS_MITG_DIS] R/W Disables the mitigation
-+ 0 by default.
-+ IA32_MCU_OPT_CTRL[GDS_MITG_LOCK] R/W Locks GDS_MITG_DIS=0. Writes
-+ to GDS_MITG_DIS are ignored
-+ Can't be cleared once set.
-+ ================================ === ============================
-+
-+GDS can also be mitigated on systems that don't have updated microcode by
-+disabling AVX. This can be done by setting "clearcpuid=avx" on the kernel
-+command-line.
-+
-+Mitigation control on the kernel command line
-+---------------------------------------------
-+The mitigation can be disabled by setting "gather_data_sampling=off" or
-+"mitigations=off" on the kernel command line. Not specifying either will
-+default to the mitigation being enabled.
-+
-+GDS System Information
-+------------------------
-+The kernel provides vulnerability status information through sysfs. For
-+GDS this can be accessed by the following sysfs file:
-+
-+/sys/devices/system/cpu/vulnerabilities/gather_data_sampling
-+
-+The possible values contained in this file are:
-+
-+ ============================== =============================================
-+ Not affected Processor not vulnerable.
-+ Vulnerable Processor vulnerable and mitigation disabled.
-+ Vulnerable: No microcode Processor vulnerable and microcode is missing
-+ mitigation.
-+ Mitigation: Microcode Processor is vulnerable and mitigation is in
-+ effect.
-+ Mitigation: Microcode (locked) Processor is vulnerable and mitigation is in
-+ effect and cannot be disabled.
-+ Unknown: Dependent on
-+ hypervisor status Running on a virtual guest processor that is
-+ affected but with no way to know if host
-+ processor is mitigated or vulnerable.
-+ ============================== =============================================
-+
-+GDS Default mitigation
-+----------------------
-+The updated microcode will enable the mitigation by default. The kernel's
-+default action is to leave the mitigation enabled.
---- a/Documentation/admin-guide/hw-vuln/index.rst
-+++ b/Documentation/admin-guide/hw-vuln/index.rst
-@@ -16,3 +16,4 @@ are configurable at compile, boot or run
- multihit.rst
- special-register-buffer-data-sampling.rst
- processor_mmio_stale_data.rst
-+ gather_data_sampling.rst
---- a/Documentation/admin-guide/kernel-parameters.txt
-+++ b/Documentation/admin-guide/kernel-parameters.txt
-@@ -1290,6 +1290,20 @@
- Format: off | on
- default: on
-
-+ gather_data_sampling=
-+ [X86,INTEL] Control the Gather Data Sampling (GDS)
-+ mitigation.
-+
-+ Gather Data Sampling is a hardware vulnerability which
-+ allows unprivileged speculative access to data which was
-+ previously stored in vector registers.
-+
-+ This issue is mitigated by default in updated microcode.
-+ The mitigation may have a performance impact but can be
-+ disabled.
-+
-+ off: Disable GDS mitigation.
-+
- gcov_persist= [GCOV] When non-zero (default), profiling data for
- kernel modules is saved and remains accessible via
- debugfs, even when the module is unloaded/reloaded.
-@@ -2555,22 +2569,23 @@
- Disable all optional CPU mitigations. This
- improves system performance, but it may also
- expose users to several CPU vulnerabilities.
-- Equivalent to: nopti [X86,PPC]
-+ Equivalent to: gather_data_sampling=off [X86]
- kpti=0 [ARM64]
-- nospectre_v1 [PPC]
-+ kvm.nx_huge_pages=off [X86]
-+ l1tf=off [X86]
-+ mds=off [X86]
-+ mmio_stale_data=off [X86]
-+ no_entry_flush [PPC]
-+ no_uaccess_flush [PPC]
- nobp=0 [S390]
-+ nopti [X86,PPC]
-+ nospectre_v1 [PPC]
- nospectre_v1 [X86]
- nospectre_v2 [X86,PPC,S390,ARM64]
-- spectre_v2_user=off [X86]
- spec_store_bypass_disable=off [X86,PPC]
-+ spectre_v2_user=off [X86]
- ssbd=force-off [ARM64]
-- l1tf=off [X86]
-- mds=off [X86]
- tsx_async_abort=off [X86]
-- kvm.nx_huge_pages=off [X86]
-- no_entry_flush [PPC]
-- no_uaccess_flush [PPC]
-- mmio_stale_data=off [X86]
-
- Exceptions:
- This does not have any effect on
---- a/arch/x86/include/asm/cpufeatures.h
-+++ b/arch/x86/include/asm/cpufeatures.h
-@@ -409,5 +409,6 @@
- #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 */
-+#define X86_BUG_GDS X86_BUG(29) /* CPU is affected by Gather Data Sampling */
-
- #endif /* _ASM_X86_CPUFEATURES_H */
---- a/arch/x86/include/asm/msr-index.h
-+++ b/arch/x86/include/asm/msr-index.h
-@@ -138,6 +138,15 @@
- * Not susceptible to Post-Barrier
- * Return Stack Buffer Predictions.
- */
-+#define ARCH_CAP_GDS_CTRL BIT(25) /*
-+ * CPU is vulnerable to Gather
-+ * Data Sampling (GDS) and
-+ * has controls for mitigation.
-+ */
-+#define ARCH_CAP_GDS_NO BIT(26) /*
-+ * CPU is not vulnerable to Gather
-+ * Data Sampling (GDS).
-+ */
-
- #define MSR_IA32_FLUSH_CMD 0x0000010b
- #define L1D_FLUSH BIT(0) /*
-@@ -156,6 +165,8 @@
- #define MSR_IA32_MCU_OPT_CTRL 0x00000123
- #define RNGDS_MITG_DIS BIT(0)
- #define FB_CLEAR_DIS BIT(3) /* CPU Fill buffer clear disable */
-+#define GDS_MITG_DIS BIT(4) /* Disable GDS mitigation */
-+#define GDS_MITG_LOCKED BIT(5) /* GDS mitigation locked */
-
- #define MSR_IA32_SYSENTER_CS 0x00000174
- #define MSR_IA32_SYSENTER_ESP 0x00000175
---- a/arch/x86/kernel/cpu/bugs.c
-+++ b/arch/x86/kernel/cpu/bugs.c
-@@ -44,6 +44,7 @@ static void __init md_clear_select_mitig
- static void __init taa_select_mitigation(void);
- static void __init mmio_select_mitigation(void);
- static void __init srbds_select_mitigation(void);
-+static void __init gds_select_mitigation(void);
-
- /* The base value of the SPEC_CTRL MSR without task-specific bits set */
- u64 x86_spec_ctrl_base;
-@@ -149,6 +150,7 @@ void __init cpu_select_mitigations(void)
- l1tf_select_mitigation();
- md_clear_select_mitigation();
- srbds_select_mitigation();
-+ gds_select_mitigation();
- }
-
- /*
-@@ -600,6 +602,120 @@ static int __init srbds_parse_cmdline(ch
- early_param("srbds", srbds_parse_cmdline);
-
- #undef pr_fmt
-+#define pr_fmt(fmt) "GDS: " fmt
-+
-+enum gds_mitigations {
-+ GDS_MITIGATION_OFF,
-+ GDS_MITIGATION_UCODE_NEEDED,
-+ GDS_MITIGATION_FULL,
-+ GDS_MITIGATION_FULL_LOCKED,
-+ GDS_MITIGATION_HYPERVISOR,
-+};
-+
-+static enum gds_mitigations gds_mitigation __ro_after_init = GDS_MITIGATION_FULL;
-+
-+static const char * const gds_strings[] = {
-+ [GDS_MITIGATION_OFF] = "Vulnerable",
-+ [GDS_MITIGATION_UCODE_NEEDED] = "Vulnerable: No microcode",
-+ [GDS_MITIGATION_FULL] = "Mitigation: Microcode",
-+ [GDS_MITIGATION_FULL_LOCKED] = "Mitigation: Microcode (locked)",
-+ [GDS_MITIGATION_HYPERVISOR] = "Unknown: Dependent on hypervisor status",
-+};
-+
-+void update_gds_msr(void)
-+{
-+ u64 mcu_ctrl_after;
-+ u64 mcu_ctrl;
-+
-+ switch (gds_mitigation) {
-+ case GDS_MITIGATION_OFF:
-+ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
-+ mcu_ctrl |= GDS_MITG_DIS;
-+ break;
-+ case GDS_MITIGATION_FULL_LOCKED:
-+ /*
-+ * The LOCKED state comes from the boot CPU. APs might not have
-+ * the same state. Make sure the mitigation is enabled on all
-+ * CPUs.
-+ */
-+ case GDS_MITIGATION_FULL:
-+ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
-+ mcu_ctrl &= ~GDS_MITG_DIS;
-+ break;
-+ case GDS_MITIGATION_UCODE_NEEDED:
-+ case GDS_MITIGATION_HYPERVISOR:
-+ return;
-+ };
-+
-+ wrmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
-+
-+ /*
-+ * Check to make sure that the WRMSR value was not ignored. Writes to
-+ * GDS_MITG_DIS will be ignored if this processor is locked but the boot
-+ * processor was not.
-+ */
-+ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl_after);
-+ WARN_ON_ONCE(mcu_ctrl != mcu_ctrl_after);
-+}
-+
-+static void __init gds_select_mitigation(void)
-+{
-+ u64 mcu_ctrl;
-+
-+ if (!boot_cpu_has_bug(X86_BUG_GDS))
-+ return;
-+
-+ if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
-+ gds_mitigation = GDS_MITIGATION_HYPERVISOR;
-+ goto out;
-+ }
-+
-+ if (cpu_mitigations_off())
-+ gds_mitigation = GDS_MITIGATION_OFF;
-+ /* Will verify below that mitigation _can_ be disabled */
-+
-+ /* No microcode */
-+ if (!(x86_read_arch_cap_msr() & ARCH_CAP_GDS_CTRL)) {
-+ gds_mitigation = GDS_MITIGATION_UCODE_NEEDED;
-+ goto out;
-+ }
-+
-+ rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl);
-+ if (mcu_ctrl & GDS_MITG_LOCKED) {
-+ if (gds_mitigation == GDS_MITIGATION_OFF)
-+ pr_warn("Mitigation locked. Disable failed.\n");
-+
-+ /*
-+ * The mitigation is selected from the boot CPU. All other CPUs
-+ * _should_ have the same state. If the boot CPU isn't locked
-+ * but others are then update_gds_msr() will WARN() of the state
-+ * mismatch. If the boot CPU is locked update_gds_msr() will
-+ * ensure the other CPUs have the mitigation enabled.
-+ */
-+ gds_mitigation = GDS_MITIGATION_FULL_LOCKED;
-+ }
-+
-+ update_gds_msr();
-+out:
-+ pr_info("%s\n", gds_strings[gds_mitigation]);
-+}
-+
-+static int __init gds_parse_cmdline(char *str)
-+{
-+ if (!str)
-+ return -EINVAL;
-+
-+ if (!boot_cpu_has_bug(X86_BUG_GDS))
-+ return 0;
-+
-+ if (!strcmp(str, "off"))
-+ gds_mitigation = GDS_MITIGATION_OFF;
-+
-+ return 0;
-+}
-+early_param("gather_data_sampling", gds_parse_cmdline);
-+
-+#undef pr_fmt
- #define pr_fmt(fmt) "Spectre V1 : " fmt
-
- enum spectre_v1_mitigation {
-@@ -2147,6 +2263,11 @@ static ssize_t retbleed_show_state(char
- return sprintf(buf, "%s\n", retbleed_strings[retbleed_mitigation]);
- }
-
-+static ssize_t gds_show_state(char *buf)
-+{
-+ return sysfs_emit(buf, "%s\n", gds_strings[gds_mitigation]);
-+}
-+
- static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr,
- char *buf, unsigned int bug)
- {
-@@ -2196,6 +2317,9 @@ static ssize_t cpu_show_common(struct de
- case X86_BUG_RETBLEED:
- return retbleed_show_state(buf);
-
-+ case X86_BUG_GDS:
-+ return gds_show_state(buf);
-+
- default:
- break;
- }
-@@ -2260,4 +2384,9 @@ ssize_t cpu_show_retbleed(struct device
- {
- return cpu_show_common(dev, attr, buf, X86_BUG_RETBLEED);
- }
-+
-+ssize_t cpu_show_gds(struct device *dev, struct device_attribute *attr, char *buf)
-+{
-+ return cpu_show_common(dev, attr, buf, X86_BUG_GDS);
-+}
- #endif
---- a/arch/x86/kernel/cpu/common.c
-+++ b/arch/x86/kernel/cpu/common.c
-@@ -1047,6 +1047,8 @@ static const __initconst struct x86_cpu_
- #define MMIO_SBDS BIT(2)
- /* CPU is affected by RETbleed, speculating where you would not expect it */
- #define RETBLEED BIT(3)
-+/* CPU is affected by GDS */
-+#define GDS BIT(4)
-
- static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
- VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS),
-@@ -1059,18 +1061,20 @@ static const struct x86_cpu_id cpu_vuln_
- VULNBL_INTEL_STEPPINGS(BROADWELL_X, X86_STEPPING_ANY, MMIO),
- VULNBL_INTEL_STEPPINGS(BROADWELL_CORE, X86_STEPPING_ANY, SRBDS),
- 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_X, X86_STEPPING_ANY, MMIO | RETBLEED | GDS),
- 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(KABYLAKE_MOBILE, X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED | GDS),
-+ VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPING_ANY, SRBDS | MMIO | RETBLEED | GDS),
- 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),
-- 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(ICELAKE_MOBILE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED | GDS),
-+ VULNBL_INTEL_STEPPINGS(ICELAKE_XEON_D, X86_STEPPING_ANY, MMIO | GDS),
-+ VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPING_ANY, MMIO | GDS),
-+ VULNBL_INTEL_STEPPINGS(COMETLAKE, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED | GDS),
-+ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED | GDS),
-+ VULNBL_INTEL_STEPPINGS(TIGERLAKE_L, X86_STEPPING_ANY, GDS),
-+ VULNBL_INTEL_STEPPINGS(TIGERLAKE, X86_STEPPING_ANY, GDS),
- VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPING_ANY, MMIO | MMIO_SBDS | RETBLEED),
-- VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPING_ANY, MMIO | RETBLEED),
-+ VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPING_ANY, MMIO | RETBLEED | GDS),
- 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_STEPPING_ANY, MMIO | MMIO_SBDS),
-@@ -1193,6 +1197,16 @@ static void __init cpu_set_bug_bits(stru
- !(ia32_cap & ARCH_CAP_PBRSB_NO))
- setup_force_cpu_bug(X86_BUG_EIBRS_PBRSB);
-
-+ /*
-+ * Check if CPU is vulnerable to GDS. If running in a virtual machine on
-+ * an affected processor, the VMM may have disabled the use of GATHER by
-+ * disabling AVX2. The only way to do this in HW is to clear XCR0[2],
-+ * which means that AVX will be disabled.
-+ */
-+ if (cpu_matches(cpu_vuln_blacklist, GDS) && !(ia32_cap & ARCH_CAP_GDS_NO) &&
-+ boot_cpu_has(X86_FEATURE_AVX))
-+ setup_force_cpu_bug(X86_BUG_GDS);
-+
- if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
- return;
-
-@@ -1666,6 +1680,8 @@ void identify_secondary_cpu(struct cpuin
- validate_apic_and_package_id(c);
- x86_spec_ctrl_setup_ap();
- update_srbds_msr();
-+ if (boot_cpu_has_bug(X86_BUG_GDS))
-+ update_gds_msr();
- }
-
- static __init int setup_noclflush(char *arg)
---- a/arch/x86/kernel/cpu/cpu.h
-+++ b/arch/x86/kernel/cpu/cpu.h
-@@ -83,6 +83,7 @@ void cpu_select_mitigations(void);
-
- extern void x86_spec_ctrl_setup_ap(void);
- extern void update_srbds_msr(void);
-+extern void update_gds_msr(void);
-
- extern u64 x86_read_arch_cap_msr(void);
-
---- a/drivers/base/cpu.c
-+++ b/drivers/base/cpu.c
-@@ -584,6 +584,12 @@ ssize_t __weak cpu_show_retbleed(struct
- return sysfs_emit(buf, "Not affected\n");
- }
-
-+ssize_t __weak cpu_show_gds(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);
-@@ -595,6 +601,7 @@ static DEVICE_ATTR(itlb_multihit, 0444,
- 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 DEVICE_ATTR(gather_data_sampling, 0444, cpu_show_gds, NULL);
-
- static struct attribute *cpu_root_vulnerabilities_attrs[] = {
- &dev_attr_meltdown.attr,
-@@ -608,6 +615,7 @@ static struct attribute *cpu_root_vulner
- &dev_attr_srbds.attr,
- &dev_attr_mmio_stale_data.attr,
- &dev_attr_retbleed.attr,
-+ &dev_attr_gather_data_sampling.attr,
- NULL
- };
-