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From: Borislav Petkov <bp@alien8.de>
To: Paul Bolle <pebolle@tiscali.nl>
Cc: Andy Lutomirski <luto@kernel.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Rusty Russell <rusty@rustcorp.com.au>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Rik van Riel <riel@redhat.com>, kvm list <kvm@vger.kernel.org>
Subject: Re: [PATCH 0/8] x86/fpu: Remove CR0.TS support
Date: Tue, 1 Nov 2016 00:48:55 +0100	[thread overview]
Message-ID: <20161031234855.qu64eamohn35jdo4@pd.tnic> (raw)
In-Reply-To: <1477955448.2230.12.camel@tiscali.nl>

On Tue, Nov 01, 2016 at 12:10:48AM +0100, Paul Bolle wrote:
> See https://lists.ozlabs.org/pipermail/lguest/2013-May/002001.html .
> Nobody cared enough to fix it. I cared enough to figure it all out. But
> I didn't understand much of the possible solutions that where suggested
> three years ago.

I'm guessing the simple fix would be this:

---
diff --git a/drivers/lguest/Kconfig b/drivers/lguest/Kconfig
index 169172d2ba05..9c08b3050bb7 100644
--- a/drivers/lguest/Kconfig
+++ b/drivers/lguest/Kconfig
@@ -1,6 +1,6 @@
 config LGUEST
 	tristate "Linux hypervisor example code"
-	depends on X86_32 && EVENTFD && TTY && PCI_DIRECT
+	depends on X86_32 && EVENTFD && TTY && PCI_DIRECT && !MICROCODE
 	select HVC_DRIVER
 	---help---
 	  This is a very simple module which allows you to run
---

but maybe the better fix is to hack in MSR emulation in lguest and
intercept the *MSR accesses and do the writes/reads in the exception
fixup and ...

I haven't looked at the lguest code, of course and whether that's easily
doable and whether it even makes sense and whether one should simply use
qemu/kvm instead and, and, and...

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

  reply	other threads:[~2016-10-31 23:49 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-31 22:18 Andy Lutomirski
2016-10-31 22:18 ` [PATCH 1/8] fpu/init: Get rid of two redundant clts() calls Andy Lutomirski
2016-11-01  7:13   ` [tip:x86/fpu] x86/fpu: " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 2/8] fpu/bugs: Stop saving and restoring CR0.TS in fpu__init_check_bugs() Andy Lutomirski
2016-11-01  7:14   ` [tip:x86/fpu] x86/fpu: " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 3/8] x86/fpu: Remove irq_ts_save() and irq_ts_restore() Andy Lutomirski
2016-11-01  7:14   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 4/8] x86/kvm: Remove host CR0.TS manipulation Andy Lutomirski
2016-11-01  7:15   ` [tip:x86/fpu] x86/fpu, kvm: " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 5/8] lguest: Remove CR0.TS support Andy Lutomirski
2016-11-01  7:15   ` [tip:x86/fpu] x86/fpu, " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 6/8] x86/fpu: #NM without FPU emulation is an error Andy Lutomirski
2016-11-01  7:16   ` [tip:x86/fpu] x86/fpu: Handle #NM without FPU emulation as " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 7/8] x86/fpu: Remove stts() Andy Lutomirski
2016-11-01  7:16   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 8/8] x86/fpu: Remove clts() Andy Lutomirski
2016-11-01  7:17   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2016-10-31 22:41 ` [PATCH 0/8] x86/fpu: Remove CR0.TS support Paul Bolle
2016-10-31 23:04   ` Borislav Petkov
2016-10-31 23:10     ` Paul Bolle
2016-10-31 23:48       ` Borislav Petkov [this message]
2016-11-01  7:51         ` Paul Bolle
2016-11-01  8:50           ` Borislav Petkov

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