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powerpc/64s/exception: machine check fix KVM guest test 

The machine_check_handle_early hypervisor guest test is skipped if
!HVMODE or MSR[HV]=0, which is wrong for PR or nested hypervisors
that could be running a guest in this state.

Test HSTATE_IN_GUEST up front and use that to branch out to the KVM
handler, then MSR[PR] alone can test for this kernel's userspace.
This matches all other interrupt handling.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-4-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2019-08-02 20:56:28 +10:00 committed by Michael Ellerman
parent 1039f62431
commit 19dbe673e6
1 changed files with 13 additions and 20 deletions
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33
arch/powerpc/kernel/exceptions-64s.S
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@ -1108,11 +1108,8 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
bl machine_check_early
std r3,RESULT(r1) /* Save result */
ld r12,_MSR(r1)
BEGIN_FTR_SECTION
b 4f
END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE)
#ifdef CONFIG_PPC_P7_NAP
#ifdef CONFIG_PPC_P7_NAP
/*
* Check if thread was in power saving mode. We come here when any
* of the following is true:
@ -1128,30 +1125,26 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
#endif
/*
* Check if we are coming from hypervisor userspace. If yes then we
* continue in host kernel in V mode to deliver the MC event.
*/
rldicl. r11,r12,4,63 /* See if MC hit while in HV mode. */
beq 5f
4: andi. r11,r12,MSR_PR /* See if coming from user. */
bne 9f /* continue in V mode if we are. */
5:
#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
BEGIN_FTR_SECTION
/*
* We are coming from kernel context. Check if we are coming from
* guest. if yes, then we can continue. We will fall through
* do_kvm_200->kvmppc_interrupt to deliver the MC event to guest.
* Check if we are coming from guest. If yes, then run the normal
* exception handler which will take the do_kvm_200->kvmppc_interrupt
* branch to deliver the MC event to guest.
*/
lbz r11,HSTATE_IN_GUEST(r13)
cmpwi r11,0 /* Check if coming from guest */
bne 9f /* continue if we are. */
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
#endif
/*
* At this point we are not sure about what context we come from.
* Check if we are coming from userspace. If yes, then run the normal
* exception handler which will deliver the MC event to this kernel.
*/
andi. r11,r12,MSR_PR /* See if coming from user. */
bne 9f /* continue in V mode if we are. */
/*
* At this point we are coming from kernel context.
* Queue up the MCE event and return from the interrupt.
* But before that, check if this is an un-recoverable exception.
* If yes, then stay on emergency stack and panic.