LKML Archive on lore.kernel.org
 help / color / Atom feed
From: "David P. Reed" <dpreed@deepplum.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "David P. Reed" <dpreed@deepplum.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Allison Randal <allison@lohutok.net>,
	Enrico Weigelt <info@metux.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kate Stewart <kstewart@linuxfoundation.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Martin Molnar <martin.molnar.programming@gmail.com>,
	Andy Lutomirski <luto@kernel.org>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	Jann Horn <jannh@google.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH v3 1/3] Correct asm VMXOFF side effects
Date: Sat,  4 Jul 2020 16:38:07 -0400
Message-ID: <20200704203809.76391-2-dpreed@deepplum.com> (raw)
In-Reply-To: <20200704203809.76391-1-dpreed@deepplum.com>

Tell gcc that VMXOFF instruction clobbers condition codes
and memory when executed.
Also, correct original comments to remove kernel-doc syntax
per Randy Dunlap's request.

Suggested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David P. Reed <dpreed@deepplum.com>
---
 arch/x86/include/asm/virtext.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
index 9aad0e0876fb..0ede8d04535a 100644
--- a/arch/x86/include/asm/virtext.h
+++ b/arch/x86/include/asm/virtext.h
@@ -30,7 +30,7 @@ static inline int cpu_has_vmx(void)
 }
 
 
-/** Disable VMX on the current CPU
+/* Disable VMX on the current CPU
  *
  * vmxoff causes a undefined-opcode exception if vmxon was not run
  * on the CPU previously. Only call this function if you know VMX
@@ -38,7 +38,7 @@ static inline int cpu_has_vmx(void)
  */
 static inline void cpu_vmxoff(void)
 {
-	asm volatile ("vmxoff");
+	asm volatile ("vmxoff" ::: "cc", "memory");
 	cr4_clear_bits(X86_CR4_VMXE);
 }
 
@@ -47,7 +47,7 @@ static inline int cpu_vmx_enabled(void)
 	return __read_cr4() & X86_CR4_VMXE;
 }
 
-/** Disable VMX if it is enabled on the current CPU
+/* Disable VMX if it is enabled on the current CPU
  *
  * You shouldn't call this if cpu_has_vmx() returns 0.
  */
@@ -57,7 +57,7 @@ static inline void __cpu_emergency_vmxoff(void)
 		cpu_vmxoff();
 }
 
-/** Disable VMX if it is supported and enabled on the current CPU
+/* Disable VMX if it is supported and enabled on the current CPU
  */
 static inline void cpu_emergency_vmxoff(void)
 {
-- 
2.26.2


  reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-25 14:45 [PATCH v2] Fix undefined operation VMXOFF during reboot and crash David P. Reed
2020-06-25 14:59 ` David P. Reed
2020-06-29 20:54   ` David P. Reed
2020-06-29 21:22     ` Andy Lutomirski
2020-06-29 21:49       ` Sean Christopherson
2020-06-29 22:46         ` David P. Reed
2020-07-04 20:38         ` [PATCH v3 0/3] " David P. Reed
2020-07-04 20:38           ` David P. Reed [this message]
2020-07-05  5:46             ` [PATCH v3 1/3] Correct asm VMXOFF side effects Randy Dunlap
2020-07-04 20:38           ` [PATCH v3 2/3] Fix undefined operation fault that can hang a cpu on crash or panic David P. Reed
2020-07-05 18:22             ` Andy Lutomirski
2020-07-05 19:52               ` David P. Reed
2020-07-05 20:55                 ` Andy Lutomirski
2020-07-05 22:07                   ` David P. Reed
2020-07-07  5:09             ` Sean Christopherson
2020-07-07 19:09               ` David P. Reed
2020-07-07 19:24                 ` Sean Christopherson
2020-07-07 19:52                   ` David P. Reed
2020-07-04 20:38           ` [PATCH v3 3/3] Force all cpus to exit VMX root operation on crash/panic reliably David P. Reed
2020-07-05 18:26             ` Andy Lutomirski
2020-07-05 20:00               ` David P. Reed
2020-07-05 20:53                 ` Andy Lutomirski
2020-07-07  5:29                   ` Sean Christopherson

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=20200704203809.76391-2-dpreed@deepplum.com \
    --to=dpreed@deepplum.com \
    --cc=alexandre.chartre@oracle.com \
    --cc=allison@lohutok.net \
    --cc=bp@alien8.de \
    --cc=dave.hansen@linux.intel.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hpa@zytor.com \
    --cc=info@metux.net \
    --cc=jannh@google.com \
    --cc=kstewart@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@amacapital.net \
    --cc=luto@kernel.org \
    --cc=martin.molnar.programming@gmail.com \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=rdunlap@infradead.org \
    --cc=sean.j.christopherson@intel.com \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /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

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git