From: Oscar Salvador <osalvador@suse.de>
To: akpm@linux-foundation.org
Cc: mhocko@suse.com, linux-mm@kvack.org, mike.kravetz@oracle.com,
david@redhat.com, aneesh.kumar@linux.vnet.ibm.com,
naoya.horiguchi@nec.com, linux-kernel@vger.kernel.org,
David Woodhouse <dwmw@amazon.co.uk>,
KarimAllah Ahmed <karahmed@amazon.de>,
gnomes@lxorguk.ukuu.org.uk, ak@linux.intel.com,
ashok.raj@intel.com, dave.hansen@intel.com,
arjan@linux.intel.com, torvalds@linux-foundation.org,
peterz@infradead.org, bp@alien8.de, pbonzini@redhat.com,
tim.c.chen@linux.intel.com, gregkh@linux-foundation.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Srivatsa S . Bhat" <srivatsa@csail.mit.edu>,
Jiri Slaby <jslaby@suse.cz>
Subject: [PATCH] x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
Date: Thu, 16 Jul 2020 14:38:10 +0200 [thread overview]
Message-ID: <20200716123810.25292-17-osalvador@suse.de> (raw)
In-Reply-To: <20200716123810.25292-1-osalvador@suse.de>
From: David Woodhouse <dwmw@amazon.co.uk>
(cherry picked from commit 20ffa1caecca4db8f79fe665acdeaa5af815a24d)
Expose indirect_branch_prediction_barrier() for use in subsequent patches.
[ tglx: Add IBPB status to spectre_v2 sysfs file ]
Co-developed-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: ak@linux.intel.com
Cc: ashok.raj@intel.com
Cc: dave.hansen@intel.com
Cc: arjan@linux.intel.com
Cc: torvalds@linux-foundation.org
Cc: peterz@infradead.org
Cc: bp@alien8.de
Cc: pbonzini@redhat.com
Cc: tim.c.chen@linux.intel.com
Cc: gregkh@linux-foundation.org
Link: https://lkml.kernel.org/r/1516896855-7642-8-git-send-email-dwmw@amazon.co.uk
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley@gmail.com>
Reviewed-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Bo Gan <ganb@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
arch/x86/include/asm/cpufeatures.h | 2 ++
arch/x86/include/asm/nospec-branch.h | 13 +++++++++++++
arch/x86/kernel/cpu/bugs.c | 10 +++++++++-
3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index a5671b849837..b4e370b5b761 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -201,6 +201,8 @@
/* Because the ALTERNATIVE scheme is for members of the X86_FEATURE club... */
#define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_PAGE_TABLE_ISOLATION w/o nokaiser */
+#define X86_FEATURE_IBPB ( 7*32+21) /* Indirect Branch Prediction Barrier enabled*/
+
/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
#define X86_FEATURE_VNMI ( 8*32+ 1) /* Intel Virtual NMI */
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 8b910416243c..41851afd44af 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -194,6 +194,19 @@ static inline void vmexit_fill_RSB(void)
#endif
}
+static inline void indirect_branch_prediction_barrier(void)
+{
+ asm volatile(ALTERNATIVE("",
+ "movl %[msr], %%ecx\n\t"
+ "movl %[val], %%eax\n\t"
+ "movl $0, %%edx\n\t"
+ "wrmsr",
+ X86_FEATURE_IBPB)
+ : : [msr] "i" (MSR_IA32_PRED_CMD),
+ [val] "i" (PRED_CMD_IBPB)
+ : "eax", "ecx", "edx", "memory");
+}
+
#endif /* __ASSEMBLY__ */
/*
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 2bbc74f8a4a8..7def33ada730 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -296,6 +296,13 @@ static void __init spectre_v2_select_mitigation(void)
setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW);
pr_info("Filling RSB on context switch\n");
}
+
+ /* Initialize Indirect Branch Prediction Barrier if supported */
+ if (boot_cpu_has(X86_FEATURE_SPEC_CTRL) ||
+ boot_cpu_has(X86_FEATURE_AMD_PRED_CMD)) {
+ setup_force_cpu_cap(X86_FEATURE_IBPB);
+ pr_info("Enabling Indirect Branch Prediction Barrier\n");
+ }
}
#undef pr_fmt
@@ -325,7 +332,8 @@ ssize_t cpu_show_spectre_v2(struct device *dev,
if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
return sprintf(buf, "Not affected\n");
- return sprintf(buf, "%s%s\n", spectre_v2_strings[spectre_v2_enabled],
+ return sprintf(buf, "%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
+ boot_cpu_has(X86_FEATURE_IBPB) ? ", IBPB" : "",
spectre_v2_module_string());
}
#endif
--
2.18.0
next prev parent reply other threads:[~2020-07-16 12:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 12:37 [PATCH v4 00/15] Hwpoison soft-offline rework Oscar Salvador
2020-07-16 12:37 ` [PATCH v4 01/15] mm,hwpoison: cleanup unused PageHuge() check Oscar Salvador
2020-07-16 12:37 ` [PATCH v4 02/15] mm, hwpoison: remove recalculating hpage Oscar Salvador
2020-07-16 12:37 ` [PATCH v4 03/15] mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED Oscar Salvador
2020-07-16 23:15 ` Mike Kravetz
2020-07-16 12:37 ` [PATCH v4 04/15] mm,madvise: Refactor madvise_inject_error Oscar Salvador
2020-07-16 12:37 ` [PATCH v4 05/15] mm,hwpoison-inject: don't pin for hwpoison_filter Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 06/15] mm,hwpoison: Un-export get_hwpoison_page and make it static Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 07/15] mm,hwpoison: Kill put_hwpoison_page Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 08/15] mm,hwpoison: remove MF_COUNT_INCREASED Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 09/15] mm,hwpoison: remove flag argument from soft offline functions Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 10/15] mm,hwpoison: Unify THP handling for hard and soft offline Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 11/15] mm,hwpoison: Rework soft offline for free pages Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 12/15] mm,hwpoison: Rework soft offline for in-use pages Oscar Salvador
2020-07-17 6:55 ` HORIGUCHI NAOYA(堀口 直也)
[not found] ` <f7387d64d0024d15a1bc821a8e19b8f0@DB7PR04MB5180.eurprd04.prod.outlook.com>
2020-07-20 8:27 ` osalvador
2020-07-22 8:08 ` osalvador
2020-07-23 10:19 ` Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 13/15] mm,hwpoison: Refactor soft_offline_huge_page and __soft_offline_page Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 14/15] mm,hwpoison: Return 0 if the page is already poisoned in soft-offline Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 15/15] mm,hwpoison: introduce MF_MSG_UNSPLIT_THP Oscar Salvador
2020-07-16 12:38 ` Oscar Salvador [this message]
2020-07-16 12:43 ` [PATCH] x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support osalvador
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