KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking

Currently, if a machine check interrupt happens while we are in the
guest, we exit the guest and call the host's machine check handler,
which tends to cause the host to panic.  Some machine checks can be
triggered by the guest; for example, if the guest creates two entries
in the SLB that map the same effective address, and then accesses that
effective address, the CPU will take a machine check interrupt.

To handle this better, when a machine check happens inside the guest,
we call a new function, kvmppc_realmode_machine_check(), while still in
real mode before exiting the guest.  On POWER7, it handles the cases
that the guest can trigger, either by flushing and reloading the SLB,
or by flushing the TLB, and then it delivers the machine check interrupt
directly to the guest without going back to the host.  On POWER7, the
OPAL firmware patches the machine check interrupt vector so that it
gets control first, and it leaves behind its analysis of the situation
in a structure pointed to by the opal_mc_evt field of the paca.  The
kvmppc_realmode_machine_check() function looks at this, and if OPAL
reports that there was no error, or that it has handled the error, we
also go straight back to the guest with a machine check.  We have to
deliver a machine check to the guest since the machine check interrupt
might have trashed valid values in SRR0/1.

If the machine check is one we can't handle in real mode, and one that
OPAL hasn't already handled, or on PPC970, we exit the guest and call
the host's machine check handler.  We do this by jumping to the
machine_check_fwnmi label, rather than absolute address 0x200, because
we don't want to re-execute OPAL's handler on POWER7.  On PPC970, the
two are equivalent because address 0x200 just contains a branch.

Then, if the host machine check handler decides that the system can
continue executing, kvmppc_handle_exit() delivers a machine check
interrupt to the guest -- once again to let the guest know that SRR0/1
have been modified.

Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix checkpatch warnings]
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 9673f73eb8db..2fdb47a19efd 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -121,6 +121,16 @@ extern char initial_stab[];
 #define PP_RXRX 3	/* Supervisor read,       User read */
 #define PP_RXXX	(HPTE_R_PP0 | 2)	/* Supervisor read, user none */
 
+/* Fields for tlbiel instruction in architecture 2.06 */
+#define TLBIEL_INVAL_SEL_MASK	0xc00	/* invalidation selector */
+#define  TLBIEL_INVAL_PAGE	0x000	/* invalidate a single page */
+#define  TLBIEL_INVAL_SET_LPID	0x800	/* invalidate a set for current LPID */
+#define  TLBIEL_INVAL_SET	0xc00	/* invalidate a set for all LPIDs */
+#define TLBIEL_INVAL_SET_MASK	0xfff000	/* set number to inval. */
+#define TLBIEL_INVAL_SET_SHIFT	12
+
+#define POWER7_TLB_SETS		128	/* # sets in POWER7 TLB */
+
 #ifndef __ASSEMBLY__
 
 struct hash_pte {