Commit 493b01de authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: Fix PAR_EL1.{PTW,S} reporting on AT S1E* 

When an AT S1E* operation fails, we need to report whether the
translation failed at S2, and whether this was during a S1 PTW.

But these two bits are not independent. PAR_EL1.PTW can only be
set of PAR_EL1.S is also set, and PAR_EL1.S can only be set on
its own when the full S1 PTW has succeeded, but that the access
itself is reporting a fault at S2.

As a result, it makes no sense to carry both ptw and s2 as parameters
to fail_s1_walk(), and they should be unified.

This fixes a number of cases where we were reporting PTW=1 *and*
S=0, which makes no sense.

Link: https://lore.kernel.org/r/20250422122612.2675672-2-maz@kernel.org


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 9c32cda4

arch/arm64/kvm/at.c

+11 −12
Original line number Diff line number Diff line
@@ -60,11 +60,11 @@ struct s1_walk_result { 
	bool	failed;

};



static void fail_s1_walk(struct s1_walk_result *wr, u8 fst, bool ptw, bool s2)

static void fail_s1_walk(struct s1_walk_result *wr, u8 fst, bool s1ptw)

{

	wr->fst		= fst;

	wr->ptw		= ptw;

	wr->s2		= s2;

	wr->ptw		= s1ptw;

	wr->s2		= s1ptw;

	wr->failed	= true;

}
@@ -345,11 +345,11 @@ static int setup_s1_walk(struct kvm_vcpu *vcpu, u32 op, struct s1_walk_info *wi, 
	return 0;



addrsz:				/* Address Size Fault level 0 */

	fail_s1_walk(wr, ESR_ELx_FSC_ADDRSZ_L(0), false, false);

	fail_s1_walk(wr, ESR_ELx_FSC_ADDRSZ_L(0), false);

	return -EFAULT;



transfault_l0:			/* Translation Fault level 0 */

	fail_s1_walk(wr, ESR_ELx_FSC_FAULT_L(0), false, false);

	fail_s1_walk(wr, ESR_ELx_FSC_FAULT_L(0), false);

	return -EFAULT;

}
@@ -380,13 +380,13 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, 
			if (ret) {

				fail_s1_walk(wr,

					     (s2_trans.esr & ~ESR_ELx_FSC_LEVEL) | level,

					     true, true);

					     true);

				return ret;

			}



			if (!kvm_s2_trans_readable(&s2_trans)) {

				fail_s1_walk(wr, ESR_ELx_FSC_PERM_L(level),

					     true, true);

					     true);



				return -EPERM;

			}
@@ -396,8 +396,7 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, 


		ret = kvm_read_guest(vcpu->kvm, ipa, &desc, sizeof(desc));

		if (ret) {

			fail_s1_walk(wr, ESR_ELx_FSC_SEA_TTW(level),

				     true, false);

			fail_s1_walk(wr, ESR_ELx_FSC_SEA_TTW(level), false);

			return ret;

		}
@@ -468,10 +467,10 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, 
	return 0;



addrsz:

	fail_s1_walk(wr, ESR_ELx_FSC_ADDRSZ_L(level), true, false);

	fail_s1_walk(wr, ESR_ELx_FSC_ADDRSZ_L(level), false);

	return -EINVAL;

transfault:

	fail_s1_walk(wr, ESR_ELx_FSC_FAULT_L(level), true, false);

	fail_s1_walk(wr, ESR_ELx_FSC_FAULT_L(level), false);

	return -ENOENT;

}
@@ -1198,7 +1197,7 @@ static u64 handle_at_slow(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) 
	}



	if (perm_fail)

		fail_s1_walk(&wr, ESR_ELx_FSC_PERM_L(wr.level), false, false);

		fail_s1_walk(&wr, ESR_ELx_FSC_PERM_L(wr.level), false);



compute_par:

	return compute_par_s1(vcpu, &wr, wi.regime);