Commit 3c0ce149 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'powerpc-5.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 

Pull powerpc fixes from Michael Ellerman:

 - Fix guest to host memory corruption in H_RTAS due to missing nargs
   check.

 - Fix guest triggerable host crashes due to bad handling of nested
   guest TM state.

 - Fix possible crashes due to incorrect reference counting in
   kvm_arch_vcpu_ioctl().

 - Two commits fixing some regressions in KVM transactional memory
   handling introduced by the recent rework of the KVM code.

Thanks to Nicholas Piggin, Alexey Kardashevskiy, and Michael Neuling.

* tag 'powerpc-5.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  KVM: PPC: Book3S HV Nested: Sanitise H_ENTER_NESTED TM state
  KVM: PPC: Book3S: Fix H_RTAS rets buffer overflow
  KVM: PPC: Fix kvm_arch_vcpu_ioctl vcpu_load leak
  KVM: PPC: Book3S: Fix CONFIG_TRANSACTIONAL_MEM=n crash
  KVM: PPC: Book3S HV P9: Fix guest TM support
parents 12e9bd16 d9c57d3e

arch/powerpc/kvm/book3s_hv.c

+2 −0
Original line number Diff line number Diff line
@@ -2697,8 +2697,10 @@ 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;

arch/powerpc/kvm/book3s_hv_nested.c

+20 −0
Original line number Diff line number Diff line
@@ -302,6 +302,9 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu) 
	if (vcpu->kvm->arch.l1_ptcr == 0)

		return H_NOT_AVAILABLE;



	if (MSR_TM_TRANSACTIONAL(vcpu->arch.shregs.msr))

		return H_BAD_MODE;



	/* copy parameters in */

	hv_ptr = kvmppc_get_gpr(vcpu, 4);

	regs_ptr = kvmppc_get_gpr(vcpu, 5);
@@ -322,6 +325,23 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu) 
	if (l2_hv.vcpu_token >= NR_CPUS)

		return H_PARAMETER;



	/*

	 * L1 must have set up a suspended state to enter the L2 in a

	 * transactional state, and only in that case. These have to be

	 * filtered out here to prevent causing a TM Bad Thing in the

	 * host HRFID. We could synthesize a TM Bad Thing back to the L1

	 * here but there doesn't seem like much point.

	 */

	if (MSR_TM_SUSPENDED(vcpu->arch.shregs.msr)) {

		if (!MSR_TM_ACTIVE(l2_regs.msr))

			return H_BAD_MODE;

	} else {

		if (l2_regs.msr & MSR_TS_MASK)

			return H_BAD_MODE;

		if (WARN_ON_ONCE(vcpu->arch.shregs.msr & MSR_TS_MASK))

			return H_BAD_MODE;

	}



	/* translate lpid */

	l2 = kvmhv_get_nested(vcpu->kvm, l2_hv.lpid, true);

	if (!l2)

arch/powerpc/kvm/book3s_hv_p9_entry.c

+22 −3
Original line number Diff line number Diff line
@@ -317,6 +317,9 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 
	 */

	mtspr(SPRN_HDEC, hdec);



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

tm_return_to_guest:

#endif

	mtspr(SPRN_DAR, vcpu->arch.shregs.dar);

	mtspr(SPRN_DSISR, vcpu->arch.shregs.dsisr);

	mtspr(SPRN_SRR0, vcpu->arch.shregs.srr0);
@@ -415,11 +418,23 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 
		 * is in real suspend mode and is trying to transition to

		 * transactional mode.

		 */

		if (local_paca->kvm_hstate.fake_suspend &&

		if (!local_paca->kvm_hstate.fake_suspend &&

				(vcpu->arch.shregs.msr & MSR_TS_S)) {

			if (kvmhv_p9_tm_emulation_early(vcpu)) {

				/* Prevent it being handled again. */

				trap = 0;

				/*

				 * Go straight back into the guest with the

				 * new NIP/MSR as set by TM emulation.

				 */

				mtspr(SPRN_HSRR0, vcpu->arch.regs.nip);

				mtspr(SPRN_HSRR1, vcpu->arch.shregs.msr);



				/*

				 * tm_return_to_guest re-loads SRR0/1, DAR,

				 * DSISR after RI is cleared, in case they had

				 * been clobbered by a MCE.

				 */

				__mtmsrd(0, 1); /* clear RI */

				goto tm_return_to_guest;

			}

		}

#endif
@@ -499,6 +514,10 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc 
	 * If we are in real mode, only switch MMU on after the MMU is

	 * switched to host, to avoid the P9_RADIX_PREFETCH_BUG.

	 */

	if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) &&

	    vcpu->arch.shregs.msr & MSR_TS_MASK)

		msr |= MSR_TS_S;



	__mtmsrd(msr, 0);



	end_timing(vcpu);

arch/powerpc/kvm/book3s_rtas.c

+22 −3
Original line number Diff line number Diff line
@@ -242,6 +242,17 @@ int kvmppc_rtas_hcall(struct kvm_vcpu *vcpu) 
	 * value so we can restore it on the way out.

	 */

	orig_rets = args.rets;

	if (be32_to_cpu(args.nargs) >= ARRAY_SIZE(args.args)) {

		/*

		 * Don't overflow our args array: ensure there is room for

		 * at least rets[0] (even if the call specifies 0 nret).

		 *

		 * Each handler must then check for the correct nargs and nret

		 * values, but they may always return failure in rets[0].

		 */

		rc = -EINVAL;

		goto fail;

	}

	args.rets = &args.args[be32_to_cpu(args.nargs)];



	mutex_lock(&vcpu->kvm->arch.rtas_token_lock);
@@ -269,9 +280,17 @@ int kvmppc_rtas_hcall(struct kvm_vcpu *vcpu) 
fail:

	/*

	 * We only get here if the guest has called RTAS with a bogus

	 * args pointer. That means we can't get to the args, and so we

	 * can't fail the RTAS call. So fail right out to userspace,

	 * which should kill the guest.

	 * args pointer or nargs/nret values that would overflow the

	 * array. That means we can't get to the args, and so we can't

	 * fail the RTAS call. So fail right out to userspace, which

	 * should kill the guest.

	 *

	 * SLOF should actually pass the hcall return value from the

	 * rtas handler call in r3, so enter_rtas could be modified to

	 * return a failure indication in r3 and we could return such

	 * errors to the guest rather than failing to host userspace.

	 * However old guests that don't test for failure could then

	 * continue silently after errors, so for now we won't do this.

	 */

	return rc;

}

arch/powerpc/kvm/powerpc.c

+2 −2
Original line number Diff line number Diff line
@@ -2048,9 +2048,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, 
	{

		struct kvm_enable_cap cap;

		r = -EFAULT;

		vcpu_load(vcpu);

		if (copy_from_user(&cap, argp, sizeof(cap)))

			goto out;

		vcpu_load(vcpu);

		r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);

		vcpu_put(vcpu);

		break;
@@ -2074,9 +2074,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, 
	case KVM_DIRTY_TLB: {

		struct kvm_dirty_tlb dirty;

		r = -EFAULT;

		vcpu_load(vcpu);

		if (copy_from_user(&dirty, argp, sizeof(dirty)))

			goto out;

		vcpu_load(vcpu);

		r = kvm_vcpu_ioctl_dirty_tlb(vcpu, &dirty);

		vcpu_put(vcpu);

		break;