diff options
Diffstat (limited to 'debian/patches/bugfix/x86/Documentation-hw-vuln-Add-documentation-for-RFDS.patch')
| -rw-r--r-- | debian/patches/bugfix/x86/Documentation-hw-vuln-Add-documentation-for-RFDS.patch | 140 |
1 files changed, 0 insertions, 140 deletions
diff --git a/debian/patches/bugfix/x86/Documentation-hw-vuln-Add-documentation-for-RFDS.patch b/debian/patches/bugfix/x86/Documentation-hw-vuln-Add-documentation-for-RFDS.patch deleted file mode 100644 index 781be97097..0000000000 --- a/debian/patches/bugfix/x86/Documentation-hw-vuln-Add-documentation-for-RFDS.patch +++ /dev/null @@ -1,140 +0,0 @@ -From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> -Date: Mon, 11 Mar 2024 12:29:43 -0700 -Subject: Documentation/hw-vuln: Add documentation for RFDS -Origin: https://git.kernel.org/linus/4e42765d1be01111df0c0275bbaf1db1acef346e - -Add the documentation for transient execution vulnerability Register -File Data Sampling (RFDS) that affects Intel Atom CPUs. - -Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> -Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> -Reviewed-by: Thomas Gleixner <tglx@linutronix.de> -Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> ---- - Documentation/admin-guide/hw-vuln/index.rst | 1 + - .../hw-vuln/reg-file-data-sampling.rst | 104 ++++++++++++++++++ - 2 files changed, 105 insertions(+) - create mode 100644 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst - -diff --git a/Documentation/admin-guide/hw-vuln/index.rst b/Documentation/admin-guide/hw-vuln/index.rst -index de99caabf65a..ff0b440ef2dc 100644 ---- a/Documentation/admin-guide/hw-vuln/index.rst -+++ b/Documentation/admin-guide/hw-vuln/index.rst -@@ -21,3 +21,4 @@ are configurable at compile, boot or run time. - cross-thread-rsb - srso - gather_data_sampling -+ reg-file-data-sampling -diff --git a/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst b/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst -new file mode 100644 -index 000000000000..0585d02b9a6c ---- /dev/null -+++ b/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst -@@ -0,0 +1,104 @@ -+================================== -+Register File Data Sampling (RFDS) -+================================== -+ -+Register File Data Sampling (RFDS) is a microarchitectural vulnerability that -+only affects Intel Atom parts(also branded as E-cores). RFDS may allow -+a malicious actor to infer data values previously used in floating point -+registers, vector registers, or integer registers. RFDS does not provide the -+ability to choose which data is inferred. CVE-2023-28746 is assigned to RFDS. -+ -+Affected Processors -+=================== -+Below is the list of affected Intel processors [#f1]_: -+ -+ =================== ============ -+ Common name Family_Model -+ =================== ============ -+ ATOM_GOLDMONT 06_5CH -+ ATOM_GOLDMONT_D 06_5FH -+ ATOM_GOLDMONT_PLUS 06_7AH -+ ATOM_TREMONT_D 06_86H -+ ATOM_TREMONT 06_96H -+ ALDERLAKE 06_97H -+ ALDERLAKE_L 06_9AH -+ ATOM_TREMONT_L 06_9CH -+ RAPTORLAKE 06_B7H -+ RAPTORLAKE_P 06_BAH -+ ATOM_GRACEMONT 06_BEH -+ RAPTORLAKE_S 06_BFH -+ =================== ============ -+ -+As an exception to this table, Intel Xeon E family parts ALDERLAKE(06_97H) and -+RAPTORLAKE(06_B7H) codenamed Catlow are not affected. They are reported as -+vulnerable in Linux because they share the same family/model with an affected -+part. Unlike their affected counterparts, they do not enumerate RFDS_CLEAR or -+CPUID.HYBRID. This information could be used to distinguish between the -+affected and unaffected parts, but it is deemed not worth adding complexity as -+the reporting is fixed automatically when these parts enumerate RFDS_NO. -+ -+Mitigation -+========== -+Intel released a microcode update that enables software to clear sensitive -+information using the VERW instruction. Like MDS, RFDS deploys the same -+mitigation strategy to force the CPU to clear the affected buffers before an -+attacker can extract the secrets. This is achieved by using the otherwise -+unused and obsolete VERW instruction in combination with a microcode update. -+The microcode clears the affected CPU buffers when the VERW instruction is -+executed. -+ -+Mitigation points -+----------------- -+VERW is executed by the kernel before returning to user space, and by KVM -+before VMentry. None of the affected cores support SMT, so VERW is not required -+at C-state transitions. -+ -+New bits in IA32_ARCH_CAPABILITIES -+---------------------------------- -+Newer processors and microcode update on existing affected processors added new -+bits to IA32_ARCH_CAPABILITIES MSR. These bits can be used to enumerate -+vulnerability and mitigation capability: -+ -+- Bit 27 - RFDS_NO - When set, processor is not affected by RFDS. -+- Bit 28 - RFDS_CLEAR - When set, processor is affected by RFDS, and has the -+ microcode that clears the affected buffers on VERW execution. -+ -+Mitigation control on the kernel command line -+--------------------------------------------- -+The kernel command line allows to control RFDS mitigation at boot time with the -+parameter "reg_file_data_sampling=". The valid arguments are: -+ -+ ========== ================================================================= -+ on If the CPU is vulnerable, enable mitigation; CPU buffer clearing -+ on exit to userspace and before entering a VM. -+ off Disables mitigation. -+ ========== ================================================================= -+ -+Mitigation default is selected by CONFIG_MITIGATION_RFDS. -+ -+Mitigation status information -+----------------------------- -+The Linux kernel provides a sysfs interface to enumerate the current -+vulnerability status of the system: whether the system is vulnerable, and -+which mitigations are active. The relevant sysfs file is: -+ -+ /sys/devices/system/cpu/vulnerabilities/reg_file_data_sampling -+ -+The possible values in this file are: -+ -+ .. list-table:: -+ -+ * - 'Not affected' -+ - The processor is not vulnerable -+ * - 'Vulnerable' -+ - The processor is vulnerable, but no mitigation enabled -+ * - 'Vulnerable: No microcode' -+ - The processor is vulnerable but microcode is not updated. -+ * - 'Mitigation: Clear Register File' -+ - The processor is vulnerable and the CPU buffer clearing mitigation is -+ enabled. -+ -+References -+---------- -+.. [#f1] Affected Processors -+ https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html --- -2.43.0 - |