This is the start of the stable review cycle for the 5.18.5 release.
There are 11 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 Thu, 16 Jun 2022 18:37:02 +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/v5.x/stable-review/patch-5.18.5-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-5.18.y
and the diffstat can be found below.
thanks,
greg k-h
-------------
Pseudo-Shortlog of commits:
Greg Kroah-Hartman <[email protected]>
Linux 5.18.5-rc1
Josh Poimboeuf <[email protected]>
x86/speculation/mmio: Print SMT warning
Pawan Gupta <[email protected]>
KVM: x86/speculation: Disable Fill buffer clear within guests
Pawan Gupta <[email protected]>
x86/speculation/mmio: Reuse SRBDS mitigation for SBDS
Pawan Gupta <[email protected]>
x86/speculation/srbds: Update SRBDS mitigation selection
Pawan Gupta <[email protected]>
x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data
Pawan Gupta <[email protected]>
x86/speculation/mmio: Enable CPU Fill buffer clearing on idle
Pawan Gupta <[email protected]>
x86/bugs: Group MDS, TAA & Processor MMIO Stale Data mitigations
Pawan Gupta <[email protected]>
x86/speculation/mmio: Add mitigation for Processor MMIO Stale Data
Pawan Gupta <[email protected]>
x86/speculation: Add a common function for MD_CLEAR mitigation update
Pawan Gupta <[email protected]>
x86/speculation/mmio: Enumerate Processor MMIO Stale Data bug
Pawan Gupta <[email protected]>
Documentation: Add documentation for Processor MMIO Stale Data
-------------
Diffstat:
Documentation/ABI/testing/sysfs-devices-system-cpu | 1 +
Documentation/admin-guide/hw-vuln/index.rst | 1 +
.../hw-vuln/processor_mmio_stale_data.rst | 246 +++++++++++++++++++++
Documentation/admin-guide/kernel-parameters.txt | 36 +++
Makefile | 4 +-
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/asm/msr-index.h | 25 +++
arch/x86/include/asm/nospec-branch.h | 2 +
arch/x86/kernel/cpu/bugs.c | 235 +++++++++++++++++---
arch/x86/kernel/cpu/common.c | 52 ++++-
arch/x86/kvm/vmx/vmx.c | 72 ++++++
arch/x86/kvm/vmx/vmx.h | 2 +
arch/x86/kvm/x86.c | 3 +
drivers/base/cpu.c | 8 +
include/linux/cpu.h | 3 +
tools/arch/x86/include/asm/cpufeatures.h | 1 +
tools/arch/x86/include/asm/msr-index.h | 25 +++
17 files changed, 676 insertions(+), 41 deletions(-)
From: Pawan Gupta <[email protected]>
commit 51802186158c74a0304f51ab963e7c2b3a2b046f upstream
Processor MMIO Stale Data is a class of vulnerabilities that may
expose data after an MMIO operation. For more details please refer to
Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
Add the Processor MMIO Stale Data bug enumeration. A microcode update
adds new bits to the MSR IA32_ARCH_CAPABILITIES, define them.
Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/include/asm/cpufeatures.h | 1
arch/x86/include/asm/msr-index.h | 19 +++++++++++++
arch/x86/kernel/cpu/common.c | 43 +++++++++++++++++++++++++++++--
tools/arch/x86/include/asm/cpufeatures.h | 1
tools/arch/x86/include/asm/msr-index.h | 19 +++++++++++++
5 files changed, 81 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -443,5 +443,6 @@
#define X86_BUG_TAA X86_BUG(22) /* CPU is affected by TSX Async Abort(TAA) */
#define X86_BUG_ITLB_MULTIHIT X86_BUG(23) /* CPU may incur MCE during certain page attribute changes */
#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 */
#endif /* _ASM_X86_CPUFEATURES_H */
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -114,6 +114,25 @@
* Not susceptible to
* TSX Async Abort (TAA) vulnerabilities.
*/
+#define ARCH_CAP_SBDR_SSDP_NO BIT(13) /*
+ * Not susceptible to SBDR and SSDP
+ * variants of Processor MMIO stale data
+ * vulnerabilities.
+ */
+#define ARCH_CAP_FBSDP_NO BIT(14) /*
+ * Not susceptible to FBSDP variant of
+ * Processor MMIO stale data
+ * vulnerabilities.
+ */
+#define ARCH_CAP_PSDP_NO BIT(15) /*
+ * Not susceptible to PSDP variant of
+ * Processor MMIO stale data
+ * vulnerabilities.
+ */
+#define ARCH_CAP_FB_CLEAR BIT(17) /*
+ * VERW clears CPU fill buffer
+ * even on MDS_NO CPUs.
+ */
#define MSR_IA32_FLUSH_CMD 0x0000010b
#define L1D_FLUSH BIT(0) /*
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1237,18 +1237,39 @@ static const __initconst struct x86_cpu_
X86_FEATURE_ANY, issues)
#define SRBDS BIT(0)
+/* CPU is affected by X86_BUG_MMIO_STALE_DATA */
+#define MMIO BIT(1)
static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS),
VULNBL_INTEL_STEPPINGS(HASWELL, X86_STEPPING_ANY, SRBDS),
VULNBL_INTEL_STEPPINGS(HASWELL_L, X86_STEPPING_ANY, SRBDS),
VULNBL_INTEL_STEPPINGS(HASWELL_G, X86_STEPPING_ANY, SRBDS),
+ VULNBL_INTEL_STEPPINGS(HASWELL_X, BIT(2) | BIT(4), MMIO),
+ VULNBL_INTEL_STEPPINGS(BROADWELL_D, X86_STEPPINGS(0x3, 0x5), MMIO),
VULNBL_INTEL_STEPPINGS(BROADWELL_G, X86_STEPPING_ANY, SRBDS),
+ VULNBL_INTEL_STEPPINGS(BROADWELL_X, X86_STEPPING_ANY, MMIO),
VULNBL_INTEL_STEPPINGS(BROADWELL, X86_STEPPING_ANY, SRBDS),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO),
VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPING_ANY, SRBDS),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE_X, BIT(3) | BIT(4) | BIT(6) |
+ BIT(7) | BIT(0xB), MMIO),
+ VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO),
VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPING_ANY, SRBDS),
- VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPINGS(0x0, 0xC), SRBDS),
- VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x0, 0xD), SRBDS),
+ VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPINGS(0x9, 0xC), SRBDS | MMIO),
+ VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPINGS(0x0, 0x8), SRBDS),
+ VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x9, 0xD), SRBDS | MMIO),
+ VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x0, 0x8), SRBDS),
+ VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPINGS(0x5, 0x5), MMIO),
+ VULNBL_INTEL_STEPPINGS(ICELAKE_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),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x1), MMIO),
+ VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), MMIO),
+ VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPINGS(0x1, 0x1), MMIO),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_D, X86_STEPPING_ANY, MMIO),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO),
{}
};
@@ -1269,6 +1290,13 @@ u64 x86_read_arch_cap_msr(void)
return ia32_cap;
}
+static bool arch_cap_mmio_immune(u64 ia32_cap)
+{
+ return (ia32_cap & ARCH_CAP_FBSDP_NO &&
+ ia32_cap & ARCH_CAP_PSDP_NO &&
+ ia32_cap & ARCH_CAP_SBDR_SSDP_NO);
+}
+
static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
{
u64 ia32_cap = x86_read_arch_cap_msr();
@@ -1328,6 +1356,17 @@ static void __init cpu_set_bug_bits(stru
cpu_matches(cpu_vuln_blacklist, SRBDS))
setup_force_cpu_bug(X86_BUG_SRBDS);
+ /*
+ * Processor MMIO Stale Data bug enumeration
+ *
+ * Affected CPU list is generally enough to enumerate the vulnerability,
+ * but for virtualization case check for ARCH_CAP MSR bits also, VMM may
+ * not want the guest to enumerate the bug.
+ */
+ if (cpu_matches(cpu_vuln_blacklist, MMIO) &&
+ !arch_cap_mmio_immune(ia32_cap))
+ setup_force_cpu_bug(X86_BUG_MMIO_STALE_DATA);
+
if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
return;
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -443,5 +443,6 @@
#define X86_BUG_TAA X86_BUG(22) /* CPU is affected by TSX Async Abort(TAA) */
#define X86_BUG_ITLB_MULTIHIT X86_BUG(23) /* CPU may incur MCE during certain page attribute changes */
#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 */
#endif /* _ASM_X86_CPUFEATURES_H */
--- a/tools/arch/x86/include/asm/msr-index.h
+++ b/tools/arch/x86/include/asm/msr-index.h
@@ -114,6 +114,25 @@
* Not susceptible to
* TSX Async Abort (TAA) vulnerabilities.
*/
+#define ARCH_CAP_SBDR_SSDP_NO BIT(13) /*
+ * Not susceptible to SBDR and SSDP
+ * variants of Processor MMIO stale data
+ * vulnerabilities.
+ */
+#define ARCH_CAP_FBSDP_NO BIT(14) /*
+ * Not susceptible to FBSDP variant of
+ * Processor MMIO stale data
+ * vulnerabilities.
+ */
+#define ARCH_CAP_PSDP_NO BIT(15) /*
+ * Not susceptible to PSDP variant of
+ * Processor MMIO stale data
+ * vulnerabilities.
+ */
+#define ARCH_CAP_FB_CLEAR BIT(17) /*
+ * VERW clears CPU fill buffer
+ * even on MDS_NO CPUs.
+ */
#define MSR_IA32_FLUSH_CMD 0x0000010b
#define L1D_FLUSH BIT(0) /*
From: Pawan Gupta <[email protected]>
commit 8cb861e9e3c9a55099ad3d08e1a3b653d29c33ca upstream
Processor MMIO Stale Data is a class of vulnerabilities that may
expose data after an MMIO operation. For details please refer to
Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst.
These vulnerabilities are broadly categorized as:
Device Register Partial Write (DRPW):
Some endpoint MMIO registers incorrectly handle writes that are
smaller than the register size. Instead of aborting the write or only
copying the correct subset of bytes (for example, 2 bytes for a 2-byte
write), more bytes than specified by the write transaction may be
written to the register. On some processors, this may expose stale
data from the fill buffers of the core that created the write
transaction.
Shared Buffers Data Sampling (SBDS):
After propagators may have moved data around the uncore and copied
stale data into client core fill buffers, processors affected by MFBDS
can leak data from the fill buffer.
Shared Buffers Data Read (SBDR):
It is similar to Shared Buffer Data Sampling (SBDS) except that the
data is directly read into the architectural software-visible state.
An attacker can use these vulnerabilities to extract data from CPU fill
buffers using MDS and TAA methods. Mitigate it by clearing the CPU fill
buffers using the VERW instruction before returning to a user or a
guest.
On CPUs not affected by MDS and TAA, user application cannot sample data
from CPU fill buffers using MDS or TAA. A guest with MMIO access can
still use DRPW or SBDR to extract data architecturally. Mitigate it with
VERW instruction to clear fill buffers before VMENTER for MMIO capable
guests.
Add a kernel parameter mmio_stale_data={off|full|full,nosmt} to control
the mitigation.
Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 36 +++++++
arch/x86/include/asm/nospec-branch.h | 2
arch/x86/kernel/cpu/bugs.c | 111 +++++++++++++++++++++++-
arch/x86/kvm/vmx/vmx.c | 3
4 files changed, 148 insertions(+), 4 deletions(-)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3105,6 +3105,7 @@
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
@@ -3126,6 +3127,7 @@
Equivalent to: l1tf=flush,nosmt [X86]
mds=full,nosmt [X86]
tsx_async_abort=full,nosmt [X86]
+ mmio_stale_data=full,nosmt [X86]
mminit_loglevel=
[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
@@ -3135,6 +3137,40 @@
log everything. Information is printed at KERN_DEBUG
so loglevel=8 may also need to be specified.
+ mmio_stale_data=
+ [X86,INTEL] Control mitigation for the Processor
+ MMIO Stale Data vulnerabilities.
+
+ Processor MMIO Stale Data is a class of
+ vulnerabilities that may expose data after an MMIO
+ operation. Exposed data could originate or end in
+ the same CPU buffers as affected by MDS and TAA.
+ Therefore, similar to MDS and TAA, the mitigation
+ is to clear the affected CPU buffers.
+
+ This parameter controls the mitigation. The
+ options are:
+
+ full - Enable mitigation on vulnerable CPUs
+
+ full,nosmt - Enable mitigation and disable SMT on
+ vulnerable CPUs.
+
+ off - Unconditionally disable mitigation
+
+ On MDS or TAA affected machines,
+ mmio_stale_data=off can be prevented by an active
+ MDS or TAA mitigation as these vulnerabilities are
+ mitigated with the same mechanism so in order to
+ disable this mitigation, you need to specify
+ mds=off and tsx_async_abort=off too.
+
+ Not specifying this option is equivalent to
+ mmio_stale_data=full.
+
+ For details see:
+ Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
+
module.sig_enforce
[KNL] When CONFIG_MODULE_SIG is set, this means that
modules without (valid) signatures will fail to load.
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -269,6 +269,8 @@ DECLARE_STATIC_KEY_FALSE(mds_idle_clear)
DECLARE_STATIC_KEY_FALSE(switch_mm_cond_l1d_flush);
+DECLARE_STATIC_KEY_FALSE(mmio_stale_data_clear);
+
#include <asm/segment.h>
/**
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -43,6 +43,7 @@ static void __init l1tf_select_mitigatio
static void __init mds_select_mitigation(void);
static void __init md_clear_update_mitigation(void);
static void __init taa_select_mitigation(void);
+static void __init mmio_select_mitigation(void);
static void __init srbds_select_mitigation(void);
static void __init l1d_flush_select_mitigation(void);
@@ -85,6 +86,10 @@ EXPORT_SYMBOL_GPL(mds_idle_clear);
*/
DEFINE_STATIC_KEY_FALSE(switch_mm_cond_l1d_flush);
+/* Controls CPU Fill buffer clear before KVM guest MMIO accesses */
+DEFINE_STATIC_KEY_FALSE(mmio_stale_data_clear);
+EXPORT_SYMBOL_GPL(mmio_stale_data_clear);
+
void __init check_bugs(void)
{
identify_boot_cpu();
@@ -119,12 +124,14 @@ void __init check_bugs(void)
l1tf_select_mitigation();
mds_select_mitigation();
taa_select_mitigation();
+ mmio_select_mitigation();
srbds_select_mitigation();
l1d_flush_select_mitigation();
/*
- * As MDS and TAA mitigations are inter-related, update and print their
- * mitigation after TAA mitigation selection is done.
+ * As MDS, TAA and MMIO Stale Data mitigations are inter-related, update
+ * and print their mitigation after MDS, TAA and MMIO Stale Data
+ * mitigation selection is done.
*/
md_clear_update_mitigation();
@@ -391,6 +398,90 @@ static int __init tsx_async_abort_parse_
early_param("tsx_async_abort", tsx_async_abort_parse_cmdline);
#undef pr_fmt
+#define pr_fmt(fmt) "MMIO Stale Data: " fmt
+
+enum mmio_mitigations {
+ MMIO_MITIGATION_OFF,
+ MMIO_MITIGATION_UCODE_NEEDED,
+ MMIO_MITIGATION_VERW,
+};
+
+/* Default mitigation for Processor MMIO Stale Data vulnerabilities */
+static enum mmio_mitigations mmio_mitigation __ro_after_init = MMIO_MITIGATION_VERW;
+static bool mmio_nosmt __ro_after_init = false;
+
+static const char * const mmio_strings[] = {
+ [MMIO_MITIGATION_OFF] = "Vulnerable",
+ [MMIO_MITIGATION_UCODE_NEEDED] = "Vulnerable: Clear CPU buffers attempted, no microcode",
+ [MMIO_MITIGATION_VERW] = "Mitigation: Clear CPU buffers",
+};
+
+static void __init mmio_select_mitigation(void)
+{
+ u64 ia32_cap;
+
+ if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA) ||
+ cpu_mitigations_off()) {
+ mmio_mitigation = MMIO_MITIGATION_OFF;
+ return;
+ }
+
+ if (mmio_mitigation == MMIO_MITIGATION_OFF)
+ return;
+
+ ia32_cap = x86_read_arch_cap_msr();
+
+ /*
+ * Enable CPU buffer clear mitigation for host and VMM, if also affected
+ * by MDS or TAA. Otherwise, enable mitigation for VMM only.
+ */
+ if (boot_cpu_has_bug(X86_BUG_MDS) || (boot_cpu_has_bug(X86_BUG_TAA) &&
+ boot_cpu_has(X86_FEATURE_RTM)))
+ static_branch_enable(&mds_user_clear);
+ else
+ static_branch_enable(&mmio_stale_data_clear);
+
+ /*
+ * Check if the system has the right microcode.
+ *
+ * CPU Fill buffer clear mitigation is enumerated by either an explicit
+ * FB_CLEAR or by the presence of both MD_CLEAR and L1D_FLUSH on MDS
+ * affected systems.
+ */
+ if ((ia32_cap & ARCH_CAP_FB_CLEAR) ||
+ (boot_cpu_has(X86_FEATURE_MD_CLEAR) &&
+ boot_cpu_has(X86_FEATURE_FLUSH_L1D) &&
+ !(ia32_cap & ARCH_CAP_MDS_NO)))
+ mmio_mitigation = MMIO_MITIGATION_VERW;
+ else
+ mmio_mitigation = MMIO_MITIGATION_UCODE_NEEDED;
+
+ if (mmio_nosmt || cpu_mitigations_auto_nosmt())
+ cpu_smt_disable(false);
+}
+
+static int __init mmio_stale_data_parse_cmdline(char *str)
+{
+ if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA))
+ return 0;
+
+ if (!str)
+ return -EINVAL;
+
+ if (!strcmp(str, "off")) {
+ mmio_mitigation = MMIO_MITIGATION_OFF;
+ } else if (!strcmp(str, "full")) {
+ mmio_mitigation = MMIO_MITIGATION_VERW;
+ } else if (!strcmp(str, "full,nosmt")) {
+ mmio_mitigation = MMIO_MITIGATION_VERW;
+ mmio_nosmt = true;
+ }
+
+ return 0;
+}
+early_param("mmio_stale_data", mmio_stale_data_parse_cmdline);
+
+#undef pr_fmt
#define pr_fmt(fmt) "" fmt
static void __init md_clear_update_mitigation(void)
@@ -402,19 +493,31 @@ static void __init md_clear_update_mitig
goto out;
/*
- * mds_user_clear is now enabled. Update MDS mitigation, if
- * necessary.
+ * mds_user_clear is now enabled. Update MDS, TAA and MMIO Stale Data
+ * mitigation, if necessary.
*/
if (mds_mitigation == MDS_MITIGATION_OFF &&
boot_cpu_has_bug(X86_BUG_MDS)) {
mds_mitigation = MDS_MITIGATION_FULL;
mds_select_mitigation();
}
+ if (taa_mitigation == TAA_MITIGATION_OFF &&
+ boot_cpu_has_bug(X86_BUG_TAA)) {
+ taa_mitigation = TAA_MITIGATION_VERW;
+ taa_select_mitigation();
+ }
+ if (mmio_mitigation == MMIO_MITIGATION_OFF &&
+ boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) {
+ mmio_mitigation = MMIO_MITIGATION_VERW;
+ mmio_select_mitigation();
+ }
out:
if (boot_cpu_has_bug(X86_BUG_MDS))
pr_info("MDS: %s\n", mds_strings[mds_mitigation]);
if (boot_cpu_has_bug(X86_BUG_TAA))
pr_info("TAA: %s\n", taa_strings[taa_mitigation]);
+ if (boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA))
+ pr_info("MMIO Stale Data: %s\n", mmio_strings[mmio_mitigation]);
}
#undef pr_fmt
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6773,6 +6773,9 @@ static noinstr void vmx_vcpu_enter_exit(
vmx_l1d_flush(vcpu);
else if (static_branch_unlikely(&mds_user_clear))
mds_clear_cpu_buffers();
+ else if (static_branch_unlikely(&mmio_stale_data_clear) &&
+ kvm_arch_has_assigned_device(vcpu->kvm))
+ mds_clear_cpu_buffers();
if (vcpu->arch.cr2 != native_read_cr2())
native_write_cr2(vcpu->arch.cr2);
From: Josh Poimboeuf <[email protected]>
commit 1dc6ff02c8bf77d71b9b5d11cbc9df77cfb28626 upstream
Similar to MDS and TAA, print a warning if SMT is enabled for the MMIO
Stale Data vulnerability.
Signed-off-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/cpu/bugs.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1258,6 +1258,7 @@ static void update_mds_branch_idle(void)
#define MDS_MSG_SMT "MDS CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html for more details.\n"
#define TAA_MSG_SMT "TAA CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/tsx_async_abort.html for more details.\n"
+#define MMIO_MSG_SMT "MMIO Stale Data CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/processor_mmio_stale_data.html for more details.\n"
void cpu_bugs_smt_update(void)
{
@@ -1302,6 +1303,16 @@ void cpu_bugs_smt_update(void)
break;
}
+ switch (mmio_mitigation) {
+ case MMIO_MITIGATION_VERW:
+ case MMIO_MITIGATION_UCODE_NEEDED:
+ if (sched_smt_active())
+ pr_warn_once(MMIO_MSG_SMT);
+ break;
+ case MMIO_MITIGATION_OFF:
+ break;
+ }
+
mutex_unlock(&spec_ctrl_mutex);
}
From: Pawan Gupta <[email protected]>
commit e5925fb867290ee924fcf2fe3ca887b792714366 upstream
MDS, TAA and Processor MMIO Stale Data mitigations rely on clearing CPU
buffers. Moreover, status of these mitigations affects each other.
During boot, it is important to maintain the order in which these
mitigations are selected. This is especially true for
md_clear_update_mitigation() that needs to be called after MDS, TAA and
Processor MMIO Stale Data mitigation selection is done.
Introduce md_clear_select_mitigation(), and select all these mitigations
from there. This reflects relationships between these mitigations and
ensures proper ordering.
Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/cpu/bugs.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -42,6 +42,7 @@ static void __init ssb_select_mitigation
static void __init l1tf_select_mitigation(void);
static void __init mds_select_mitigation(void);
static void __init md_clear_update_mitigation(void);
+static void __init md_clear_select_mitigation(void);
static void __init taa_select_mitigation(void);
static void __init mmio_select_mitigation(void);
static void __init srbds_select_mitigation(void);
@@ -122,19 +123,10 @@ void __init check_bugs(void)
spectre_v2_select_mitigation();
ssb_select_mitigation();
l1tf_select_mitigation();
- mds_select_mitigation();
- taa_select_mitigation();
- mmio_select_mitigation();
+ md_clear_select_mitigation();
srbds_select_mitigation();
l1d_flush_select_mitigation();
- /*
- * As MDS, TAA and MMIO Stale Data mitigations are inter-related, update
- * and print their mitigation after MDS, TAA and MMIO Stale Data
- * mitigation selection is done.
- */
- md_clear_update_mitigation();
-
arch_smt_update();
#ifdef CONFIG_X86_32
@@ -520,6 +512,20 @@ out:
pr_info("MMIO Stale Data: %s\n", mmio_strings[mmio_mitigation]);
}
+static void __init md_clear_select_mitigation(void)
+{
+ mds_select_mitigation();
+ taa_select_mitigation();
+ mmio_select_mitigation();
+
+ /*
+ * As MDS, TAA and MMIO Stale Data mitigations are inter-related, update
+ * and print their mitigation after MDS, TAA and MMIO Stale Data
+ * mitigation selection is done.
+ */
+ md_clear_update_mitigation();
+}
+
#undef pr_fmt
#define pr_fmt(fmt) "SRBDS: " fmt
From: Pawan Gupta <[email protected]>
commit f52ea6c26953fed339aa4eae717ee5c2133c7ff2 upstream
Processor MMIO Stale Data mitigation uses similar mitigation as MDS and
TAA. In preparation for adding its mitigation, add a common function to
update all mitigations that depend on MD_CLEAR.
[ bp: Add a newline in md_clear_update_mitigation() to separate
statements better. ]
Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/cpu/bugs.c | 59 +++++++++++++++++++++++++--------------------
1 file changed, 33 insertions(+), 26 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -41,7 +41,7 @@ static void __init spectre_v2_select_mit
static void __init ssb_select_mitigation(void);
static void __init l1tf_select_mitigation(void);
static void __init mds_select_mitigation(void);
-static void __init mds_print_mitigation(void);
+static void __init md_clear_update_mitigation(void);
static void __init taa_select_mitigation(void);
static void __init srbds_select_mitigation(void);
static void __init l1d_flush_select_mitigation(void);
@@ -123,10 +123,10 @@ void __init check_bugs(void)
l1d_flush_select_mitigation();
/*
- * As MDS and TAA mitigations are inter-related, print MDS
- * mitigation until after TAA mitigation selection is done.
+ * As MDS and TAA mitigations are inter-related, update and print their
+ * mitigation after TAA mitigation selection is done.
*/
- mds_print_mitigation();
+ md_clear_update_mitigation();
arch_smt_update();
@@ -267,14 +267,6 @@ static void __init mds_select_mitigation
}
}
-static void __init mds_print_mitigation(void)
-{
- if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off())
- return;
-
- pr_info("%s\n", mds_strings[mds_mitigation]);
-}
-
static int __init mds_cmdline(char *str)
{
if (!boot_cpu_has_bug(X86_BUG_MDS))
@@ -329,7 +321,7 @@ static void __init taa_select_mitigation
/* TSX previously disabled by tsx=off */
if (!boot_cpu_has(X86_FEATURE_RTM)) {
taa_mitigation = TAA_MITIGATION_TSX_DISABLED;
- goto out;
+ return;
}
if (cpu_mitigations_off()) {
@@ -343,7 +335,7 @@ static void __init taa_select_mitigation
*/
if (taa_mitigation == TAA_MITIGATION_OFF &&
mds_mitigation == MDS_MITIGATION_OFF)
- goto out;
+ return;
if (boot_cpu_has(X86_FEATURE_MD_CLEAR))
taa_mitigation = TAA_MITIGATION_VERW;
@@ -375,18 +367,6 @@ static void __init taa_select_mitigation
if (taa_nosmt || cpu_mitigations_auto_nosmt())
cpu_smt_disable(false);
-
- /*
- * Update MDS mitigation, if necessary, as the mds_user_clear is
- * now enabled for TAA mitigation.
- */
- if (mds_mitigation == MDS_MITIGATION_OFF &&
- boot_cpu_has_bug(X86_BUG_MDS)) {
- mds_mitigation = MDS_MITIGATION_FULL;
- mds_select_mitigation();
- }
-out:
- pr_info("%s\n", taa_strings[taa_mitigation]);
}
static int __init tsx_async_abort_parse_cmdline(char *str)
@@ -411,6 +391,33 @@ static int __init tsx_async_abort_parse_
early_param("tsx_async_abort", tsx_async_abort_parse_cmdline);
#undef pr_fmt
+#define pr_fmt(fmt) "" fmt
+
+static void __init md_clear_update_mitigation(void)
+{
+ if (cpu_mitigations_off())
+ return;
+
+ if (!static_key_enabled(&mds_user_clear))
+ goto out;
+
+ /*
+ * mds_user_clear is now enabled. Update MDS mitigation, if
+ * necessary.
+ */
+ if (mds_mitigation == MDS_MITIGATION_OFF &&
+ boot_cpu_has_bug(X86_BUG_MDS)) {
+ mds_mitigation = MDS_MITIGATION_FULL;
+ mds_select_mitigation();
+ }
+out:
+ if (boot_cpu_has_bug(X86_BUG_MDS))
+ pr_info("MDS: %s\n", mds_strings[mds_mitigation]);
+ if (boot_cpu_has_bug(X86_BUG_TAA))
+ pr_info("TAA: %s\n", taa_strings[taa_mitigation]);
+}
+
+#undef pr_fmt
#define pr_fmt(fmt) "SRBDS: " fmt
enum srbds_mitigations {
From: Pawan Gupta <[email protected]>
commit 22cac9c677c95f3ac5c9244f8ca0afdc7c8afb19 upstream
Currently, Linux disables SRBDS mitigation on CPUs not affected by
MDS and have the TSX feature disabled. On such CPUs, secrets cannot
be extracted from CPU fill buffers using MDS or TAA. Without SRBDS
mitigation, Processor MMIO Stale Data vulnerabilities can be used to
extract RDRAND, RDSEED, and EGETKEY data.
Do not disable SRBDS mitigation by default when CPU is also affected by
Processor MMIO Stale Data vulnerabilities.
Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/cpu/bugs.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -595,11 +595,13 @@ static void __init srbds_select_mitigati
return;
/*
- * Check to see if this is one of the MDS_NO systems supporting
- * TSX that are only exposed to SRBDS when TSX is enabled.
+ * Check to see if this is one of the MDS_NO systems supporting TSX that
+ * are only exposed to SRBDS when TSX is enabled or when CPU is affected
+ * by Processor MMIO Stale Data vulnerability.
*/
ia32_cap = x86_read_arch_cap_msr();
- if ((ia32_cap & ARCH_CAP_MDS_NO) && !boot_cpu_has(X86_FEATURE_RTM))
+ if ((ia32_cap & ARCH_CAP_MDS_NO) && !boot_cpu_has(X86_FEATURE_RTM) &&
+ !boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA))
srbds_mitigation = SRBDS_MITIGATION_TSX_OFF;
else if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
srbds_mitigation = SRBDS_MITIGATION_HYPERVISOR;
From: Pawan Gupta <[email protected]>
commit a992b8a4682f119ae035a01b40d4d0665c4a2875 upstream
The Shared Buffers Data Sampling (SBDS) variant of Processor MMIO Stale
Data vulnerabilities may expose RDRAND, RDSEED and SGX EGETKEY data.
Mitigation for this is added by a microcode update.
As some of the implications of SBDS are similar to SRBDS, SRBDS mitigation
infrastructure can be leveraged by SBDS. Set X86_BUG_SRBDS and use SRBDS
mitigation.
Mitigation is enabled by default; use srbds=off to opt-out. Mitigation
status can be checked from below file:
/sys/devices/system/cpu/vulnerabilities/srbds
Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/cpu/common.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1239,6 +1239,8 @@ static const __initconst struct x86_cpu_
#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)
static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS),
@@ -1260,16 +1262,17 @@ static const struct x86_cpu_id cpu_vuln_
VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPINGS(0x0, 0x8), SRBDS),
VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x9, 0xD), SRBDS | MMIO),
VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x0, 0x8), SRBDS),
- VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPINGS(0x5, 0x5), MMIO),
+ VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPINGS(0x5, 0x5), MMIO | MMIO_SBDS),
VULNBL_INTEL_STEPPINGS(ICELAKE_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),
- VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x1), MMIO),
- VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), 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(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_D, X86_STEPPING_ANY, MMIO),
- VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO | MMIO_SBDS),
{}
};
@@ -1350,10 +1353,14 @@ static void __init cpu_set_bug_bits(stru
/*
* SRBDS affects CPUs which support RDRAND or RDSEED and are listed
* in the vulnerability blacklist.
+ *
+ * Some of the implications and mitigation of Shared Buffers Data
+ * Sampling (SBDS) are similar to SRBDS. Give SBDS same treatment as
+ * SRBDS.
*/
if ((cpu_has(c, X86_FEATURE_RDRAND) ||
cpu_has(c, X86_FEATURE_RDSEED)) &&
- cpu_matches(cpu_vuln_blacklist, SRBDS))
+ cpu_matches(cpu_vuln_blacklist, SRBDS | MMIO_SBDS))
setup_force_cpu_bug(X86_BUG_SRBDS);
/*
From: Pawan Gupta <[email protected]>
commit 4419470191386456e0b8ed4eb06a70b0021798a6 upstream
Add the admin guide for Processor MMIO stale data vulnerabilities.
Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
Documentation/admin-guide/hw-vuln/index.rst | 1
Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst | 246 ++++++++++
2 files changed, 247 insertions(+)
create mode 100644 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
--- a/Documentation/admin-guide/hw-vuln/index.rst
+++ b/Documentation/admin-guide/hw-vuln/index.rst
@@ -17,3 +17,4 @@ are configurable at compile, boot or run
special-register-buffer-data-sampling.rst
core-scheduling.rst
l1d_flush.rst
+ processor_mmio_stale_data.rst
--- /dev/null
+++ b/Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
@@ -0,0 +1,246 @@
+=========================================
+Processor MMIO Stale Data Vulnerabilities
+=========================================
+
+Processor MMIO Stale Data Vulnerabilities are a class of memory-mapped I/O
+(MMIO) vulnerabilities that can expose data. The sequences of operations for
+exposing data range from simple to very complex. Because most of the
+vulnerabilities require the attacker to have access to MMIO, many environments
+are not affected. System environments using virtualization where MMIO access is
+provided to untrusted guests may need mitigation. These vulnerabilities are
+not transient execution attacks. However, these vulnerabilities may propagate
+stale data into core fill buffers where the data can subsequently be inferred
+by an unmitigated transient execution attack. Mitigation for these
+vulnerabilities includes a combination of microcode update and software
+changes, depending on the platform and usage model. Some of these mitigations
+are similar to those used to mitigate Microarchitectural Data Sampling (MDS) or
+those used to mitigate Special Register Buffer Data Sampling (SRBDS).
+
+Data Propagators
+================
+Propagators are operations that result in stale data being copied or moved from
+one microarchitectural buffer or register to another. Processor MMIO Stale Data
+Vulnerabilities are operations that may result in stale data being directly
+read into an architectural, software-visible state or sampled from a buffer or
+register.
+
+Fill Buffer Stale Data Propagator (FBSDP)
+-----------------------------------------
+Stale data may propagate from fill buffers (FB) into the non-coherent portion
+of the uncore on some non-coherent writes. Fill buffer propagation by itself
+does not make stale data architecturally visible. Stale data must be propagated
+to a location where it is subject to reading or sampling.
+
+Sideband Stale Data Propagator (SSDP)
+-------------------------------------
+The sideband stale data propagator (SSDP) is limited to the client (including
+Intel Xeon server E3) uncore implementation. The sideband response buffer is
+shared by all client cores. For non-coherent reads that go to sideband
+destinations, the uncore logic returns 64 bytes of data to the core, including
+both requested data and unrequested stale data, from a transaction buffer and
+the sideband response buffer. As a result, stale data from the sideband
+response and transaction buffers may now reside in a core fill buffer.
+
+Primary Stale Data Propagator (PSDP)
+------------------------------------
+The primary stale data propagator (PSDP) is limited to the client (including
+Intel Xeon server E3) uncore implementation. Similar to the sideband response
+buffer, the primary response buffer is shared by all client cores. For some
+processors, MMIO primary reads will return 64 bytes of data to the core fill
+buffer including both requested data and unrequested stale data. This is
+similar to the sideband stale data propagator.
+
+Vulnerabilities
+===============
+Device Register Partial Write (DRPW) (CVE-2022-21166)
+-----------------------------------------------------
+Some endpoint MMIO registers incorrectly handle writes that are smaller than
+the register size. Instead of aborting the write or only copying the correct
+subset of bytes (for example, 2 bytes for a 2-byte write), more bytes than
+specified by the write transaction may be written to the register. On
+processors affected by FBSDP, this may expose stale data from the fill buffers
+of the core that created the write transaction.
+
+Shared Buffers Data Sampling (SBDS) (CVE-2022-21125)
+----------------------------------------------------
+After propagators may have moved data around the uncore and copied stale data
+into client core fill buffers, processors affected by MFBDS can leak data from
+the fill buffer. It is limited to the client (including Intel Xeon server E3)
+uncore implementation.
+
+Shared Buffers Data Read (SBDR) (CVE-2022-21123)
+------------------------------------------------
+It is similar to Shared Buffer Data Sampling (SBDS) except that the data is
+directly read into the architectural software-visible state. It is limited to
+the client (including Intel Xeon server E3) uncore implementation.
+
+Affected Processors
+===================
+Not all the CPUs are affected by all the variants. For instance, most
+processors for the server market (excluding Intel Xeon E3 processors) are
+impacted by only Device Register Partial Write (DRPW).
+
+Below is the list of affected Intel processors [#f1]_:
+
+ =================== ============ =========
+ Common name Family_Model Steppings
+ =================== ============ =========
+ HASWELL_X 06_3FH 2,4
+ SKYLAKE_L 06_4EH 3
+ BROADWELL_X 06_4FH All
+ SKYLAKE_X 06_55H 3,4,6,7,11
+ BROADWELL_D 06_56H 3,4,5
+ SKYLAKE 06_5EH 3
+ ICELAKE_X 06_6AH 4,5,6
+ ICELAKE_D 06_6CH 1
+ ICELAKE_L 06_7EH 5
+ ATOM_TREMONT_D 06_86H All
+ LAKEFIELD 06_8AH 1
+ KABYLAKE_L 06_8EH 9 to 12
+ ATOM_TREMONT 06_96H 1
+ ATOM_TREMONT_L 06_9CH 0
+ KABYLAKE 06_9EH 9 to 13
+ COMETLAKE 06_A5H 2,3,5
+ COMETLAKE_L 06_A6H 0,1
+ ROCKETLAKE 06_A7H 1
+ =================== ============ =========
+
+If a CPU is in the affected processor list, but not affected by a variant, it
+is indicated by new bits in MSR IA32_ARCH_CAPABILITIES. As described in a later
+section, mitigation largely remains the same for all the variants, i.e. to
+clear the CPU fill buffers via VERW instruction.
+
+New bits in MSRs
+================
+Newer processors and microcode update on existing affected processors added new
+bits to IA32_ARCH_CAPABILITIES MSR. These bits can be used to enumerate
+specific variants of Processor MMIO Stale Data vulnerabilities and mitigation
+capability.
+
+MSR IA32_ARCH_CAPABILITIES
+--------------------------
+Bit 13 - SBDR_SSDP_NO - When set, processor is not affected by either the
+ Shared Buffers Data Read (SBDR) vulnerability or the sideband stale
+ data propagator (SSDP).
+Bit 14 - FBSDP_NO - When set, processor is not affected by the Fill Buffer
+ Stale Data Propagator (FBSDP).
+Bit 15 - PSDP_NO - When set, processor is not affected by Primary Stale Data
+ Propagator (PSDP).
+Bit 17 - FB_CLEAR - When set, VERW instruction will overwrite CPU fill buffer
+ values as part of MD_CLEAR operations. Processors that do not
+ enumerate MDS_NO (meaning they are affected by MDS) but that do
+ enumerate support for both L1D_FLUSH and MD_CLEAR implicitly enumerate
+ FB_CLEAR as part of their MD_CLEAR support.
+Bit 18 - FB_CLEAR_CTRL - Processor supports read and write to MSR
+ IA32_MCU_OPT_CTRL[FB_CLEAR_DIS]. On such processors, the FB_CLEAR_DIS
+ bit can be set to cause the VERW instruction to not perform the
+ FB_CLEAR action. Not all processors that support FB_CLEAR will support
+ FB_CLEAR_CTRL.
+
+MSR IA32_MCU_OPT_CTRL
+---------------------
+Bit 3 - FB_CLEAR_DIS - When set, VERW instruction does not perform the FB_CLEAR
+action. This may be useful to reduce the performance impact of FB_CLEAR in
+cases where system software deems it warranted (for example, when performance
+is more critical, or the untrusted software has no MMIO access). Note that
+FB_CLEAR_DIS has no impact on enumeration (for example, it does not change
+FB_CLEAR or MD_CLEAR enumeration) and it may not be supported on all processors
+that enumerate FB_CLEAR.
+
+Mitigation
+==========
+Like MDS, all variants of Processor MMIO Stale Data vulnerabilities have 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.
+
+Kernel reuses the MDS function to invoke the buffer clearing:
+
+ mds_clear_cpu_buffers()
+
+On MDS affected CPUs, the kernel already invokes CPU buffer clear on
+kernel/userspace, hypervisor/guest and C-state (idle) transitions. No
+additional mitigation is needed on such CPUs.
+
+For CPUs not affected by MDS or TAA, mitigation is needed only for the attacker
+with MMIO capability. Therefore, VERW is not required for kernel/userspace. For
+virtualization case, VERW is only needed at VMENTER for a guest with MMIO
+capability.
+
+Mitigation points
+-----------------
+Return to user space
+^^^^^^^^^^^^^^^^^^^^
+Same mitigation as MDS when affected by MDS/TAA, otherwise no mitigation
+needed.
+
+C-State transition
+^^^^^^^^^^^^^^^^^^
+Control register writes by CPU during C-state transition can propagate data
+from fill buffer to uncore buffers. Execute VERW before C-state transition to
+clear CPU fill buffers.
+
+Guest entry point
+^^^^^^^^^^^^^^^^^
+Same mitigation as MDS when processor is also affected by MDS/TAA, otherwise
+execute VERW at VMENTER only for MMIO capable guests. On CPUs not affected by
+MDS/TAA, guest without MMIO access cannot extract secrets using Processor MMIO
+Stale Data vulnerabilities, so there is no need to execute VERW for such guests.
+
+Mitigation control on the kernel command line
+---------------------------------------------
+The kernel command line allows to control the Processor MMIO Stale Data
+mitigations at boot time with the option "mmio_stale_data=". The valid
+arguments for this option are:
+
+ ========== =================================================================
+ full If the CPU is vulnerable, enable mitigation; CPU buffer clearing
+ on exit to userspace and when entering a VM. Idle transitions are
+ protected as well. It does not automatically disable SMT.
+ full,nosmt Same as full, with SMT disabled on vulnerable CPUs. This is the
+ complete mitigation.
+ off Disables mitigation completely.
+ ========== =================================================================
+
+If the CPU is affected and mmio_stale_data=off is not supplied on the kernel
+command line, then the kernel selects the appropriate mitigation.
+
+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/mmio_stale_data
+
+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: Clear CPU buffers attempted, no microcode'
+ - The processor is vulnerable, but microcode is not updated. The
+ mitigation is enabled on a best effort basis.
+ * - 'Mitigation: Clear CPU buffers'
+ - The processor is vulnerable and the CPU buffer clearing mitigation is
+ enabled.
+
+If the processor is vulnerable then the following information is appended to
+the above information:
+
+ ======================== ===========================================
+ 'SMT vulnerable' SMT is enabled
+ 'SMT disabled' SMT is disabled
+ 'SMT Host state unknown' Kernel runs in a VM, Host SMT state unknown
+ ======================== ===========================================
+
+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
On 6/14/22 11:40, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +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/v5.x/stable-review/patch-5.18.5-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-5.18.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
On ARCH_BRCMSTB using 32-bit and 64-bit ARM kernels:
Tested-by: Florian Fainelli <[email protected]>
--
Florian
On 6/15/22 01:40, Greg Kroah-Hartman wrote:
> + .. list-table::
> +
> + * - 'Not affected'
> + - The processor is not vulnerable
> + * - 'Vulnerable'
> + - The processor is vulnerable, but no mitigation enabled
> + * - 'Vulnerable: Clear CPU buffers attempted, no microcode'
> + - The processor is vulnerable, but microcode is not updated. The
> + mitigation is enabled on a best effort basis.
> + * - 'Mitigation: Clear CPU buffers'
> + - The processor is vulnerable and the CPU buffer clearing mitigation is
> + enabled.
> +
> +If the processor is vulnerable then the following information is appended to
> +the above information:
> +
> + ======================== ===========================================
> + 'SMT vulnerable' SMT is enabled
> + 'SMT disabled' SMT is disabled
> + 'SMT Host state unknown' Kernel runs in a VM, Host SMT state unknown
> + ======================== ===========================================
> +
Why is list-table used in sysfs table instead of usual ASCII table in SMT
vulnerabilities list above? I think using ASCII table in both cases is enough
for the purpose.
--
An old man doll... just what I always wanted! - Clara
On Tue, 14 Jun 2022 20:40:37 +0200, Greg Kroah-Hartman <[email protected]> wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +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/v5.x/stable-review/patch-5.18.5-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-5.18.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
>
5.18.5-rc1 Successfully Compiled and booted on my Raspberry PI 4b (8g) (bcm2711)
Tested-by: Fox Chen <[email protected]>
hallo Greg
5.18.5-rc1
compiles, boots and runs here on x86_64
(Intel i5-11400, Fedora 36)
Tested-by: Ronald Warsow <[email protected]
Thanks
Ronald
On 6/14/22 12:40 PM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +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/v5.x/stable-review/patch-5.18.5-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-5.18.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 <[email protected]>
thanks,
-- Shuah
On Wed, Jun 15, 2022 at 08:06:37AM +0700, Bagas Sanjaya wrote:
>On 6/15/22 01:40, Greg Kroah-Hartman wrote:
>> + .. list-table::
>> +
>> + * - 'Not affected'
>> + - The processor is not vulnerable
>> + * - 'Vulnerable'
>> + - The processor is vulnerable, but no mitigation enabled
>> + * - 'Vulnerable: Clear CPU buffers attempted, no microcode'
>> + - The processor is vulnerable, but microcode is not updated. The
>> + mitigation is enabled on a best effort basis.
>> + * - 'Mitigation: Clear CPU buffers'
>> + - The processor is vulnerable and the CPU buffer clearing mitigation is
>> + enabled.
>> +
>> +If the processor is vulnerable then the following information is appended to
>> +the above information:
>> +
>> + ======================== ===========================================
>> + 'SMT vulnerable' SMT is enabled
>> + 'SMT disabled' SMT is disabled
>> + 'SMT Host state unknown' Kernel runs in a VM, Host SMT state unknown
>> + ======================== ===========================================
>> +
>
>Why is list-table used in sysfs table instead of usual ASCII table in SMT
>vulnerabilities list above? I think using ASCII table in both cases is enough
>for the purpose.
Maybe you are right (and I am no expert in this), but quite a few
documents use list-table for sysfs status:
https://www.kernel.org/doc/Documentation/admin-guide/hw-vuln/mds.rst
https://www.kernel.org/doc/Documentation/admin-guide/hw-vuln/spectre.rst
https://www.kernel.org/doc/Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
On 6/14/22 11:40 AM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +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/v5.x/stable-review/patch-5.18.5-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-5.18.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
Built and booted successfully on RISC-V RV64 (HiFive Unmatched).
Tested-by: Ron Economos <[email protected]>
On Tue, Jun 14, 2022 at 08:40:37PM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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.
Successfully cross-compiled for arm (multi_v7_defconfig, GCC 12.1.0,
ARMv7 with neon FPU) and arm64 (bcm2711_defconfig, GCC 12.1.0).
Tested-by: Bagas Sanjaya <[email protected]>
--
An old man doll... just what I always wanted! - Clara
On Tue, Jun 14, 2022 at 08:40:37PM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +0000.
> Anything received after that time might be too late.
Hi Greg,
5.18.5-rc1 tested.
Run tested on:
- Intel Tiger Lake x86_64 (nuc11 i7-1165G7)
- Allwinner H6 (Tanix TX6)
In addition - build tested for:
- Allwinner A64
- Allwinner H3
- Allwinner H5
- NXP iMX6
- NXP iMX8
- Qualcomm Dragonboard
- Rockchip RK3288
- Rockchip RK3328
- Rockchip RK3399pro
- Samsung Exynos
Tested-by: Rudi Heitbaum <[email protected]>
--
Rudi
Pawan Gupta <[email protected]> writes:
> On Wed, Jun 15, 2022 at 08:06:37AM +0700, Bagas Sanjaya wrote:
>>On 6/15/22 01:40, Greg Kroah-Hartman wrote:
>>> + .. list-table::
>>> +
>>> + * - 'Not affected'
>>> + - The processor is not vulnerable
>>> + * - 'Vulnerable'
>>> + - The processor is vulnerable, but no mitigation enabled
>>> + * - 'Vulnerable: Clear CPU buffers attempted, no microcode'
>>> + - The processor is vulnerable, but microcode is not updated. The
>>> + mitigation is enabled on a best effort basis.
>>> + * - 'Mitigation: Clear CPU buffers'
>>> + - The processor is vulnerable and the CPU buffer clearing mitigation is
>>> + enabled.
>>> +
>>> +If the processor is vulnerable then the following information is appended to
>>> +the above information:
>>> +
>>> + ======================== ===========================================
>>> + 'SMT vulnerable' SMT is enabled
>>> + 'SMT disabled' SMT is disabled
>>> + 'SMT Host state unknown' Kernel runs in a VM, Host SMT state unknown
>>> + ======================== ===========================================
>>> +
>>
>>Why is list-table used in sysfs table instead of usual ASCII table in SMT
>>vulnerabilities list above? I think using ASCII table in both cases is enough
>>for the purpose.
>
> Maybe you are right (and I am no expert in this), but quite a few
> documents use list-table for sysfs status:
>
> https://www.kernel.org/doc/Documentation/admin-guide/hw-vuln/mds.rst
> https://www.kernel.org/doc/Documentation/admin-guide/hw-vuln/spectre.rst
> https://www.kernel.org/doc/Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
List-table should really be avoided whenever possible; it makes reading
the plain-text files difficult at best. I'd like to see the existing
uses taken out over time.
This isn't really something to be addressed in the stable updates,
though.
jon
On Wed, 15 Jun 2022 at 00:16, Greg Kroah-Hartman
<[email protected]> wrote:
>
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +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/v5.x/stable-review/patch-5.18.5-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-5.18.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 <[email protected]>
## Build
* kernel: 5.18.5-rc1
* git: https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc
* git branch: linux-5.18.y
* git commit: 0e32b2c68ea4d90e0ecca45afd07dcf5d594de7e
* git describe: v5.18.4-12-g0e32b2c68ea4
* test details:
https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-5.18.y/build/v5.18.4-12-g0e32b2c68ea4
## Test Regressions (compared to v5.18.4)
No test regressions found.
## Metric Regressions (compared to v5.18.4)
No metric regressions found.
## Test Fixes (compared to v5.18.4)
No test fixes found.
## Metric Fixes (compared to v5.18.4)
No metric fixes found.
## Test result summary
total: 127841, pass: 115630, fail: 544, skip: 10874, xfail: 793
## Build Summary
* arc: 10 total, 10 passed, 0 failed
* arm: 319 total, 316 passed, 3 failed
* arm64: 64 total, 62 passed, 2 failed
* i386: 57 total, 50 passed, 7 failed
* mips: 41 total, 38 passed, 3 failed
* parisc: 14 total, 14 passed, 0 failed
* powerpc: 65 total, 56 passed, 9 failed
* riscv: 32 total, 27 passed, 5 failed
* s390: 23 total, 20 passed, 3 failed
* sh: 26 total, 24 passed, 2 failed
* sparc: 14 total, 14 passed, 0 failed
* x86_64: 62 total, 58 passed, 4 failed
## Test suites summary
* fwts
* igt-gpu-tools
* kselftest-android
* kselftest-breakpoints
* kselftest-capabilities
* kselftest-cgroup
* kselftest-clone3
* kselftest-core
* kselftest-cpu-hotplug
* kselftest-cpufreq
* kselftest-drivers-dma-buf
* kselftest-efivarfs
* kselftest-filesystems
* kselftest-filesystems-binderfs
* kselftest-firmware
* kselftest-fpu
* kselftest-gpio
* kselftest-ipc
* kselftest-ir
* kselftest-kcmp
* kselftest-lib
* kselftest-membarrier
* kselftest-netfilter
* kselftest-nsfs
* kselftest-openat2
* kselftest-pid_namespace
* kselftest-pidfd
* kselftest-proc
* kselftest-pstore
* kselftest-rseq
* kselftest-rtc
* kselftest-seccomp
* kselftest-sigaltstack
* kselftest-size
* kselftest-splice
* kselftest-static_keys
* kselftest-sync
* kselftest-sysctl
* kselftest-tc-testing
* kselftest-timens
* kselftest-timers
* kselftest-tmpfs
* kselftest-tpm2
* kselftest-user
* kselftest-vm
* kselftest-zram
* kunit
* kunit/15
* kunit/261
* kunit/3
* kunit/427
* kunit/90
* kvm-unit-tests
* libgpiod
* libhugetlbfs
* log-parser-boot
* log-parser-test
* ltp-cap_bounds
* ltp-cap_bounds-tests
* ltp-commands
* ltp-commands-tests
* ltp-containers
* ltp-containers-tests
* ltp-controllers-tests
* ltp-cpuhotplug-tests
* ltp-crypto
* ltp-crypto-tests
* ltp-cve-tests
* ltp-dio-tests
* ltp-fcntl-locktests
* ltp-fcntl-locktests-tests
* ltp-filecaps
* ltp-filecaps-tests
* ltp-fs
* ltp-fs-tests
* ltp-fs_bind
* ltp-fs_bind-tests
* ltp-fs_perms_simple
* ltp-fs_perms_simple-tests
* ltp-fsx
* ltp-fsx-tests
* ltp-hugetlb
* ltp-hugetlb-tests
* ltp-io
* ltp-io-tests
* ltp-ipc
* ltp-ipc-tests
* ltp-math-tests
* ltp-mm-tests
* ltp-nptl
* ltp-nptl-tests
* ltp-open-posix-tests
* ltp-pty
* ltp-pty-tests
* ltp-sched
* ltp-sched-tests
* ltp-securebits
* ltp-securebits-tests
* ltp-smoke
* ltp-syscalls-tests
* ltp-tracing-tests
* network-basic-tests
* packetdrill
* perf
* perf/Zstd-perf.data-compression
* rcutorture
* ssuite
* v4l2-compliance
* vdso
--
Linaro LKFT
https://lkft.linaro.org
On Tue, Jun 14, 2022 at 08:40:37PM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +0000.
> Anything received after that time might be too late.
>
Build results:
total: 154 pass: 154 fail: 0
Qemu test results:
total: 489 pass: 489 fail: 0
Tested-by: Guenter Roeck <[email protected]>
Guenter
On 14/06/2022 19:40, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +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/v5.x/stable-review/patch-5.18.5-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-5.18.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
All tests passing for Tegra ...
Test results for stable-v5.18:
10 builds: 10 pass, 0 fail
28 boots: 28 pass, 0 fail
130 tests: 130 pass, 0 fail
Linux version: 5.18.5-rc1-g0e32b2c68ea4
Boards tested: tegra124-jetson-tk1, tegra186-p2771-0000,
tegra194-p2972-0000, tegra194-p3509-0000+p3668-0000,
tegra20-ventana, tegra210-p2371-2180,
tegra210-p3450-0000, tegra30-cardhu-a04
Tested-by: Jon Hunter <[email protected]>
Jon
--
nvpublic
On Tue, Jun 14, 2022 at 08:40:37PM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.18.5 release.
> There are 11 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 Thu, 16 Jun 2022 18:37:02 +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/v5.x/stable-review/patch-5.18.5-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-5.18.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
Tested rc1 against the Fedora build system (aarch64, armv7, ppc64le,
s390x, x86_64), and boot tested x86_64. No regressions noted.
Tested-by: Justin M. Forbes <[email protected]>