SVM instructions fail with SVME bit enabled

[Paolo Montesel]

I was trying to use QEMU/TCG to emulate some stuff that uses SVM.
I know SVM is only partially implemented but I gave it a try anyway.

I found that if SVM is enabled in the same basic block in which there's a call to VMSAVE/etc,
the call fails as illegal op because the flags don't get updated correctly.

The pseudocode for the asm I'm running is:

```
EFER |= SVME; set the appropriate bit with wrmsr
vmsave
```

This is an example of the relevant translate.c code:

```
            if (!(s->flags & HF_SVME_MASK) || !s->pe) {
                goto illegal_op;
            }
            if (s->cpl != 0) {
                gen_exception(s, EXCP0D_GPF, pc_start - s->cs_base);
                break;
            }
```

s->flags doesn't get updated after the wrmsr instruction and so QEMU raises an illegal opcode interrupt.

A quick fix is to make the tb end after `wrmsr` instructions, but it's an hack afaik.
I'm not too comfortable with QEMU's code, so I don't know what a proper fix would be.

Cheers,

thebabush

[Thomas Huth (th-huth)]

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[Launchpad Janitor (janitor)]

[Expired for QEMU because there has been no activity for 60 days.]