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Commit 43ff3f65 authored by Paul Mackerras's avatar Paul Mackerras
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KVM: PPC: Book3S HV: Make sure we don't re-enter guest without XIVE loaded 



This fixes a bug where it is possible to enter a guest on a POWER9
system without having the XIVE (interrupt controller) context loaded.
This can happen because we unload the XIVE context from the CPU
before doing the real-mode handling for machine checks.  After the
real-mode handler runs, it is possible that we re-enter the guest
via a fast path which does not load the XIVE context.

To fix this, we move the unloading of the XIVE context to come after
the real-mode machine check handler is called.

Fixes: 5af50993 ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent 5855564c

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+20 −20
Original line number Diff line number Diff line
@@ -1423,6 +1423,26 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) 
	blt	deliver_guest_interrupt



guest_exit_cont:		/* r9 = vcpu, r12 = trap, r13 = paca */

	/* Save more register state  */

	mfdar	r6

	mfdsisr	r7

	std	r6, VCPU_DAR(r9)

	stw	r7, VCPU_DSISR(r9)

	/* don't overwrite fault_dar/fault_dsisr if HDSI */

	cmpwi	r12,BOOK3S_INTERRUPT_H_DATA_STORAGE

	beq	mc_cont

	std	r6, VCPU_FAULT_DAR(r9)

	stw	r7, VCPU_FAULT_DSISR(r9)



	/* See if it is a machine check */

	cmpwi	r12, BOOK3S_INTERRUPT_MACHINE_CHECK

	beq	machine_check_realmode

mc_cont:

#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING

	addi	r3, r9, VCPU_TB_RMEXIT

	mr	r4, r9

	bl	kvmhv_accumulate_time

#endif

#ifdef CONFIG_KVM_XICS

	/* We are exiting, pull the VP from the XIVE */

	lwz	r0, VCPU_XIVE_PUSHED(r9)
@@ -1460,26 +1480,6 @@ guest_exit_cont: /* r9 = vcpu, r12 = trap, r13 = paca */ 
	eieio

1:

#endif /* CONFIG_KVM_XICS */

	/* Save more register state  */

	mfdar	r6

	mfdsisr	r7

	std	r6, VCPU_DAR(r9)

	stw	r7, VCPU_DSISR(r9)

	/* don't overwrite fault_dar/fault_dsisr if HDSI */

	cmpwi	r12,BOOK3S_INTERRUPT_H_DATA_STORAGE

	beq	mc_cont

	std	r6, VCPU_FAULT_DAR(r9)

	stw	r7, VCPU_FAULT_DSISR(r9)



	/* See if it is a machine check */

	cmpwi	r12, BOOK3S_INTERRUPT_MACHINE_CHECK

	beq	machine_check_realmode

mc_cont:

#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING

	addi	r3, r9, VCPU_TB_RMEXIT

	mr	r4, r9

	bl	kvmhv_accumulate_time

#endif



	mr 	r3, r12

	/* Increment exit count, poke other threads to exit */