Commit f3c99f97 authored by Paul Mackerras's avatar Paul Mackerras Committed by Michael Ellerman
Browse files

KVM: PPC: Book3S HV: Don't access HFSCR, LPIDR or LPCR when running nested 



When running as a nested hypervisor, this avoids reading hypervisor
privileged registers (specifically HFSCR, LPIDR and LPCR) at startup;
instead reasonable default values are used.  This also avoids writing
LPIDR in the single-vcpu entry/exit path.

Also, this removes the check for CPU_FTR_HVMODE in kvmppc_mmu_hv_init()
since its only caller already checks this.

Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 9d0b048d

arch/powerpc/kvm/book3s_64_mmu_hv.c

+3 −4
Original line number Diff line number Diff line
@@ -268,13 +268,12 @@ int kvmppc_mmu_hv_init(void) 
{

	unsigned long host_lpid, rsvd_lpid;



	if (!cpu_has_feature(CPU_FTR_HVMODE))

		return -EINVAL;



	if (!mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE))

		return -EINVAL;



	/* POWER7 has 10-bit LPIDs (12-bit in POWER8) */

	host_lpid = 0;

	if (cpu_has_feature(CPU_FTR_HVMODE))

		host_lpid = mfspr(SPRN_LPID);

	rsvd_lpid = LPID_RSVD;

arch/powerpc/kvm/book3s_hv.c

+21 −12
Original line number Diff line number Diff line
@@ -2174,15 +2174,18 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm, 
	 * Set the default HFSCR for the guest from the host value.

	 * This value is only used on POWER9.

	 * On POWER9, we want to virtualize the doorbell facility, so we

	 * turn off the HFSCR bit, which causes those instructions to trap.

	 * don't set the HFSCR_MSGP bit, and that causes those instructions

	 * to trap and then we emulate them.

	 */

	vcpu->arch.hfscr = mfspr(SPRN_HFSCR);

	vcpu->arch.hfscr = HFSCR_TAR | HFSCR_EBB | HFSCR_PM | HFSCR_BHRB |

		HFSCR_DSCR | HFSCR_VECVSX | HFSCR_FP;

	if (cpu_has_feature(CPU_FTR_HVMODE)) {

		vcpu->arch.hfscr &= mfspr(SPRN_HFSCR);

		if (cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST))

			vcpu->arch.hfscr |= HFSCR_TM;

	else if (!cpu_has_feature(CPU_FTR_TM_COMP))

		vcpu->arch.hfscr &= ~HFSCR_TM;

	if (cpu_has_feature(CPU_FTR_ARCH_300))

		vcpu->arch.hfscr &= ~HFSCR_MSGP;

	}

	if (cpu_has_feature(CPU_FTR_TM_COMP))

		vcpu->arch.hfscr |= HFSCR_TM;



	kvmppc_mmu_book3s_hv_init(vcpu);
@@ -4006,8 +4009,10 @@ int kvmhv_run_single_vcpu(struct kvm_run *kvm_run, 


	srcu_read_unlock(&kvm->srcu, srcu_idx);



	if (cpu_has_feature(CPU_FTR_HVMODE)) {

		mtspr(SPRN_LPID, kvm->arch.host_lpid);

		isync();

	}



	trace_hardirqs_off();

	set_irq_happened(trap);
@@ -4634,9 +4639,13 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm) 
		kvm->arch.host_sdr1 = mfspr(SPRN_SDR1);



	/* Init LPCR for virtual RMA mode */

	if (cpu_has_feature(CPU_FTR_HVMODE)) {

		kvm->arch.host_lpid = mfspr(SPRN_LPID);

		kvm->arch.host_lpcr = lpcr = mfspr(SPRN_LPCR);

		lpcr &= LPCR_PECE | LPCR_LPES;

	} else {

		lpcr = 0;

	}

	lpcr |= (4UL << LPCR_DPFD_SH) | LPCR_HDICE |

		LPCR_VPM0 | LPCR_VPM1;

	kvm->arch.vrma_slb_v = SLB_VSID_B_1T |

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