From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Borislav Petkov <bp@suse.de>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Subject: [PATCH 5.4 14/51] x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS
Date: Wed, 5 Oct 2022 13:32:02 +0200 [thread overview]
Message-ID: <20221005113210.929116747@linuxfoundation.org> (raw)
In-Reply-To: <20221005113210.255710920@linuxfoundation.org>
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: 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
@@ -4553,6 +4553,7 @@
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
@@ -234,6 +234,7 @@ 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");
}
@@ -1951,7 +1989,7 @@ 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) {
next prev parent reply other threads:[~2022-10-05 11:36 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-05 11:31 [PATCH 5.4 00/51] 5.4.217-rc1 review Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 01/51] Revert "x86/speculation: Add RSB VM Exit protections" Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 02/51] Revert "x86/cpu: Add a steppings field to struct x86_cpu_id" Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 03/51] x86/devicetable: Move x86 specific macro out of generic code Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 04/51] x86/cpu: Add consistent CPU match macros Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 05/51] x86/cpu: Add a steppings field to struct x86_cpu_id Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 06/51] x86/kvm/vmx: Make noinstr clean Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 07/51] x86/cpufeatures: Move RETPOLINE flags to word 11 Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 08/51] x86/bugs: Report AMD retbleed vulnerability Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 09/51] x86/bugs: Add AMD retbleed= boot parameter Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 10/51] x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value Greg Kroah-Hartman
2022-10-05 11:31 ` [PATCH 5.4 11/51] x86/entry: Remove skip_r11rcx Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 12/51] x86/entry: Add kernel IBRS implementation Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 13/51] x86/bugs: Optimize SPEC_CTRL MSR writes Greg Kroah-Hartman
2022-10-05 11:32 ` Greg Kroah-Hartman [this message]
2022-10-05 11:32 ` [PATCH 5.4 15/51] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 16/51] x86/bugs: Report Intel retbleed vulnerability Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 17/51] intel_idle: Disable IBRS during long idle Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 18/51] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 19/51] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 20/51] x86/speculation: Fix firmware entry SPEC_CTRL handling Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 21/51] x86/speculation: Fix SPEC_CTRL write on SMT state change Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 22/51] x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 23/51] x86/speculation: Remove x86_spec_ctrl_mask Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 24/51] KVM/VMX: Use TEST %REG,%REG instead of CMP $0,%REG in vmenter.S Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 25/51] KVM/nVMX: Use __vmx_vcpu_run in nested_vmx_check_vmentry_hw Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 26/51] KVM: VMX: Flatten __vmx_vcpu_run() Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 27/51] KVM: VMX: Convert launched argument to flags Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 28/51] KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 29/51] KVM: VMX: Fix IBRS handling after vmexit Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 30/51] x86/speculation: Fill RSB on vmexit for IBRS Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 31/51] x86/common: Stamp out the stepping madness Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 32/51] x86/cpu/amd: Enumerate BTC_NO Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 33/51] x86/bugs: Add Cannon lake to RETBleed affected CPU list Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 34/51] x86/speculation: Disable RRSBA behavior Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 35/51] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 36/51] x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 37/51] x86/speculation: Add RSB VM Exit protections Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 38/51] xfs: fix misuse of the XFS_ATTR_INCOMPLETE flag Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 39/51] xfs: introduce XFS_MAX_FILEOFF Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 40/51] xfs: truncate should remove all blocks, not just to the end of the page cache Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 41/51] xfs: fix s_maxbytes computation on 32-bit kernels Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 42/51] xfs: fix IOCB_NOWAIT handling in xfs_file_dio_aio_read Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 43/51] xfs: refactor remote attr value buffer invalidation Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 44/51] xfs: fix memory corruption during " Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 45/51] xfs: move incore structures out of xfs_da_format.h Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 46/51] xfs: streamline xfs_attr3_leaf_inactive Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 47/51] xfs: fix uninitialized variable in xfs_attr3_leaf_inactive Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 48/51] xfs: remove unused variable done Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 49/51] Revert "drm/amdgpu: use dirty framebuffer helper" Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 50/51] Makefile.extrawarn: Move -Wcast-function-type-strict to W=1 Greg Kroah-Hartman
2022-10-05 11:32 ` [PATCH 5.4 51/51] docs: update mediator information in CoC docs Greg Kroah-Hartman
2022-10-05 19:12 ` [PATCH 5.4 00/51] 5.4.217-rc1 review Daniel Díaz
2022-10-05 19:29 ` Thadeu Lima de Souza Cascardo
2022-10-05 19:29 ` Guenter Roeck
2022-10-06 9:32 ` Jon Hunter
2022-10-06 19:02 ` Naresh Kamboju
2022-10-06 19:39 ` Slade Watkins
2022-10-06 20:01 ` Allen Pais
2022-10-07 14:35 ` zhouzhixiu
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