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[PATCH v5 8/9] x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y

From Andy Lutomirski <luto@kernel.org>
Newsgroups linux.kernel
Subject [PATCH v5 8/9] x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y
Date 2016-04-02 16:10 +0200
Message-ID <rjupt-4TG-11@gated-at.bofh.it> (permalink)
References <rjups-4TG-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Enabling CONFIG_PARAVIRT had an unintended side effect: rdmsr turned
into rdmsr_safe and wrmsr turned into wrmsr_safe, even on bare
metal.  Undo that by using the new unsafe paravirt MSR hooks.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/include/asm/paravirt.h | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 68297d87e85c..0c99f10874e4 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -151,24 +151,21 @@ static inline int paravirt_write_msr_safe(unsigned msr,
 	return PVOP_CALL3(int, pv_cpu_ops.write_msr_safe, msr, low, high);
 }
 
-/* These should all do BUG_ON(_err), but our headers are too tangled. */
 #define rdmsr(msr, val1, val2)			\
 do {						\
-	int _err;				\
-	u64 _l = paravirt_read_msr_safe(msr, &_err);	\
+	u64 _l = paravirt_read_msr(msr);	\
 	val1 = (u32)_l;				\
 	val2 = _l >> 32;			\
 } while (0)
 
 #define wrmsr(msr, val1, val2)			\
 do {						\
-	paravirt_write_msr_safe(msr, val1, val2);	\
+	paravirt_write_msr(msr, val1, val2);	\
 } while (0)
 
 #define rdmsrl(msr, val)			\
 do {						\
-	int _err;				\
-	val = paravirt_read_msr_safe(msr, &_err);	\
+	val = paravirt_read_msr(msr);		\
 } while (0)
 
 static inline void wrmsrl(unsigned msr, u64 val)
-- 
2.5.5

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Thread

[PATCH v5 0/9] Improve non-"safe" MSR access failure handling Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
  [PATCH v5 5/9] x86/paravirt: Add _safe to the read_msr and write_msr PV hooks Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
    Re: [PATCH v5 5/9] x86/paravirt: Add _safe to the read_msr and  write_msr PV hooks Borislav Petkov <bp@alien8.de> - 2016-04-03 10:50 +0200
      Re: [PATCH v5 5/9] x86/paravirt: Add _safe to the read_msr and  write_msr PV hooks Andy Lutomirski <luto@amacapital.net> - 2016-04-03 15:30 +0200
        Re: [PATCH v5 5/9] x86/paravirt: Add _safe to the read_msr and  write_msr PV hooks Borislav Petkov <bp@alien8.de> - 2016-04-03 16:10 +0200
    [tip:x86/asm] x86/paravirt: Add _safe to the read_ms()r and  write_msr() PV callbacks tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-04-13 13:50 +0200
  [PATCH v5 8/9] x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
    [tip:x86/asm] x86/paravirt: Make "unsafe" MSR accesses unsafe even  if PARAVIRT=y tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-04-13 13:50 +0200
  [PATCH v5 2/9] x86/head: Move the early NMI fixup into C Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
    [tip:x86/asm] x86/head: Move the early NMI fixup into C tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-04-13 13:50 +0200
  [PATCH v5 3/9] x86/head: Move early exception panic code into early_fixup_exception Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
    Re: [PATCH v5 3/9] x86/head: Move early exception panic code into  early_fixup_exception Borislav Petkov <bp@alien8.de> - 2016-04-02 20:40 +0200
      Re: [PATCH v5 3/9] x86/head: Move early exception panic code into early_fixup_exception Andy Lutomirski <luto@amacapital.net> - 2016-04-02 22:20 +0200
        Re: [PATCH v5 3/9] x86/head: Move early exception panic code into  early_fixup_exception Borislav Petkov <bp@alien8.de> - 2016-04-02 22:50 +0200
          Re: [PATCH v5 3/9] x86/head: Move early exception panic code into early_fixup_exception Andy Lutomirski <luto@amacapital.net> - 2016-04-02 23:00 +0200
            Re: [PATCH v5 3/9] x86/head: Move early exception panic code into  early_fixup_exception Jan Kara <jack@suse.cz> - 2016-04-04 14:00 +0200
              Re: [PATCH v5 3/9] x86/head: Move early exception panic code into  early_fixup_exception Peter Zijlstra <peterz@infradead.org> - 2016-04-04 14:50 +0200
              Re: [PATCH v5 3/9] x86/head: Move early exception panic code into  early_fixup_exception Arjan van de Ven <arjan@linux.intel.com> - 2016-04-04 17:40 +0200
              Re: [PATCH v5 3/9] x86/head: Move early exception panic code into early_fixup_exception Andy Lutomirski <luto@amacapital.net> - 2016-04-04 17:40 +0200
                Re: [PATCH v5 3/9] x86/head: Move early exception panic code into  early_fixup_exception Peter Zijlstra <peterz@infradead.org> - 2016-04-04 18:10 +0200
                Re: [PATCH v5 3/9] x86/head: Move early exception panic code into  early_fixup_exception Borislav Petkov <bp@alien8.de> - 2016-04-04 21:40 +0200
                Re: [PATCH v5 3/9] x86/head: Move early exception panic code into early_fixup_exception Andy Lutomirski <luto@amacapital.net> - 2016-04-04 23:40 +0200
                Re: [PATCH v5 3/9] x86/head: Move early exception panic code into  early_fixup_exception Borislav Petkov <bp@alien8.de> - 2016-04-04 23:50 +0200
    [tip:x86/asm] x86/head: Move early exception panic code into  early_fixup_exception() tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-04-13 13:50 +0200
  [PATCH v5 7/9] x86/paravirt: Add paravirt_{read,write}_msr Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
    Re: [Xen-devel] [PATCH v5 7/9] x86/paravirt: Add paravirt_{read,  write}_msr David Vrabel <david.vrabel@citrix.com> - 2016-04-04 18:40 +0200
      Re: [Xen-devel] [PATCH v5 7/9] x86/paravirt: Add paravirt_{read, write}_msr Andy Lutomirski <luto@amacapital.net> - 2016-04-04 18:50 +0200
    [tip:x86/asm] x86/paravirt: Add paravirt_{read,write}_msr() tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-04-13 13:50 +0200
  [PATCH v5 1/9] x86/head: Pass a real pt_regs and trapnr to early_fixup_exception Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
    [tip:x86/asm] x86/head: Pass a real pt_regs and trapnr to  early_fixup_exception() tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-04-13 13:50 +0200
  [PATCH v5 6/9] x86/msr: Carry on after a non-"safe" MSR access fails Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
    [tip:x86/asm] x86/msr: Carry on after a non-"safe" MSR access fails tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-04-13 13:50 +0200
  [PATCH v5 9/9] x86/msr: Set the return value to zero when native_rdmsr_safe fails Andy Lutomirski <luto@kernel.org> - 2016-04-02 16:10 +0200
    [tip:x86/asm] x86/msr: Set the return value to zero when  native_rdmsr_safe() fails tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-04-13 13:50 +0200
  Re: [PATCH v5 0/9] Improve non-"safe" MSR access failure handling Linus Torvalds <torvalds@linux-foundation.org> - 2016-04-02 16:30 +0200
    Re: [PATCH v5 0/9] Improve non-"safe" MSR access failure handling Andy Lutomirski <luto@amacapital.net> - 2016-04-02 17:20 +0200
      Re: [PATCH v5 0/9] Improve non-"safe" MSR access failure handling Linus Torvalds <torvalds@linux-foundation.org> - 2016-04-02 17:30 +0200
  Re: [PATCH v5 0/9] Improve non-"safe" MSR access failure handling Borislav Petkov <bp@alien8.de> - 2016-04-04 18:30 +0200
  Re: [Xen-devel] [PATCH v5 0/9] Improve non-"safe" MSR access failure  handling Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-04-05 17:40 +0200

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