Commit b85dadd4 authored Jul 16, 2021 by Nicholas Piggin Committed by Greg Kroah-Hartman Jul 28, 2021

KVM: PPC: Book3S: Fix CONFIG_TRANSACTIONAL_MEM=n crash



[ Upstream commit bd31ecf44b8e18ccb1e5f6b50f85de6922a60de3 ]

When running CPU_FTR_P9_TM_HV_ASSIST, HFSCR[TM] is set for the guest
even if the host has CONFIG_TRANSACTIONAL_MEM=n, which causes it to be
unprepared to handle guest exits while transactional.

Normal guests don't have a problem because the HTM capability will not
be advertised, but a rogue or buggy one could crash the host.

Fixes: 4bb3c7a0 ("KVM: PPC: Book3S HV: Work around transactional memory bugs in POWER9")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210716024310.164448-1-npiggin@gmail.com


Signed-off-by: Sasha Levin <sashal@kernel.org>

parent b3224bd3

arch/powerpc/kvm/book3s_hv.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -2306,8 +2306,10 @@ static struct kvm_vcpu kvmppc_core_vcpu_create_hv(struct kvm kvm,
		HFSCR_DSCR \| HFSCR_VECVSX \| HFSCR_FP;
		if (cpu_has_feature(CPU_FTR_HVMODE)) {
		vcpu->arch.hfscr &= mfspr(SPRN_HFSCR);
		#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
		if (cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST))
		vcpu->arch.hfscr \|= HFSCR_TM;
		#endif
		}
		if (cpu_has_feature(CPU_FTR_TM_COMP))
		vcpu->arch.hfscr \|= HFSCR_TM;