Re: [PATCH 0/8] x86/fpu: Remove CR0.TS support

[Borislav Petkov]

On Tue, Nov 01, 2016 at 12:10:48AM +0100, Paul Bolle wrote:
> SeeÂhttps://lists.ozlabs.org/pipermail/lguest/2013-May/002001.htmlÂ;.
> 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.