From: Nicholas Piggin npiggin@gmail.com
stable inclusion from stable-5.10.54 commit fcbad8e18d31e46d06c3458c8dcad897b8194cd9 bugzilla: 175586 https://gitee.com/openeuler/kernel/issues/I4DVDU
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ 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: 4bb3c7a0208f ("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 Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- arch/powerpc/kvm/book3s_hv.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 2325b7a6e95f..bd7350a608d4 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -2366,8 +2366,10 @@ static int kvmppc_core_vcpu_create_hv(struct kvm_vcpu *vcpu) HFSCR_DSCR | HFSCR_VECVSX | HFSCR_FP | HFSCR_PREFIX; 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;