All of lore.kernel.org
 help / color / mirror / Atom feed
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


  parent reply	other threads:[~2020-07-16 12:38 UTC|newest]

Thread overview: 24+ 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
2020-07-17 14:49 ` [PATCH v4 00/15] Hwpoison soft-offline rework Qian Cai

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200716123810.25292-17-osalvador@suse.de \
    --to=osalvador@suse.de \
    --cc=ak@linux.intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=aneesh.kumar@linux.vnet.ibm.com \
    --cc=arjan@linux.intel.com \
    --cc=ashok.raj@intel.com \
    --cc=bp@alien8.de \
    --cc=dave.hansen@intel.com \
    --cc=david@redhat.com \
    --cc=dwmw@amazon.co.uk \
    --cc=gnomes@lxorguk.ukuu.org.uk \
    --cc=gregkh@linux-foundation.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=jslaby@suse.cz \
    --cc=karahmed@amazon.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@suse.com \
    --cc=mike.kravetz@oracle.com \
    --cc=naoya.horiguchi@nec.com \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    --cc=srivatsa@csail.mit.edu \
    --cc=tim.c.chen@linux.intel.com \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: [PATCH] x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.