Commit 35e4d7fe authored by Marc Zyngier's avatar Marc Zyngier
Browse files

Merge branch kvm-arm64/at-fixes-6.16 into kvmarm-master/next 



* kvm-arm64/at-fixes-6.16:
  : .
  : Set of fixes for Address Translation (AT) instruction emulation,
  : which affect the (not yet upstream) NV support.
  :
  : From the cover letter:
  :
  : "Here's a small series of fixes for KVM's implementation of address
  : translation (aka the AT S1* instructions), addressing a number of
  : issues in increasing levels of severity:
  :
  : - We misreport PAR_EL1.PTW in a number of occasions, including state
  :   that is not possible as per the architecture definition
  :
  : - We don't handle access faults at all, and that doesn't play very
  :   well with the rest of the VNCR stuff
  :
  : - AT S1E{0,1} from EL2 with HCR_EL2.{E2H,TGE}={1,1} will absolutely
  :   take the host down, no questions asked"
  : .
  KVM: arm64: Don't feed uninitialised data to HCR_EL2
  KVM: arm64: Teach address translation about access faults
  KVM: arm64: Fix PAR_EL1.{PTW,S} reporting on AT S1E*

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parents fef3acf5 3e4d5972

arch/arm64/kvm/at.c

+36 −23
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;

		}
@@ -457,6 +456,11 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, 
	if (check_output_size(desc & GENMASK(47, va_bottom), wi))

		goto addrsz;



	if (!(desc & PTE_AF)) {

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

		return -EACCES;

	}



	va_bottom += contiguous_bit_shift(desc, wi, level);



	wr->failed = false;
@@ -468,10 +472,10 @@ 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;

}
@@ -488,7 +492,6 @@ struct mmu_config { 
	u64	sctlr;

	u64	vttbr;

	u64	vtcr;

	u64	hcr;

};



static void __mmu_config_save(struct mmu_config *config)
@@ -511,13 +514,10 @@ static void __mmu_config_save(struct mmu_config *config) 
	config->sctlr	= read_sysreg_el1(SYS_SCTLR);

	config->vttbr	= read_sysreg(vttbr_el2);

	config->vtcr	= read_sysreg(vtcr_el2);

	config->hcr	= read_sysreg(hcr_el2);

}



static void __mmu_config_restore(struct mmu_config *config)

{

	write_sysreg(config->hcr,	hcr_el2);



	/*

	 * ARM errata 1165522 and 1530923 require TGE to be 1 before

	 * we update the guest state.
@@ -1198,7 +1198,7 @@ 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);
@@ -1210,7 +1210,8 @@ static u64 handle_at_slow(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) 
 * If the translation is unsuccessful, the value may only contain

 * PAR_EL1.F, and cannot be taken at face value. It isn't an

 * indication of the translation having failed, only that the fast

 * path did not succeed, *unless* it indicates a S1 permission fault.

 * path did not succeed, *unless* it indicates a S1 permission or

 * access fault.

 */

static u64 __kvm_at_s1e01_fast(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)

{
@@ -1266,8 +1267,8 @@ static u64 __kvm_at_s1e01_fast(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) 
	__load_stage2(mmu, mmu->arch);



skip_mmu_switch:

	/* Clear TGE, enable S2 translation, we're rolling */

	write_sysreg((config.hcr & ~HCR_TGE) | HCR_VM,	hcr_el2);

	/* Temporarily switch back to guest context */

	write_sysreg(vcpu->arch.hcr_el2, hcr_el2);

	isb();



	switch (op) {
@@ -1299,6 +1300,8 @@ static u64 __kvm_at_s1e01_fast(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) 
	if (!fail)

		par = read_sysreg_par();



	write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);



	if (!(vcpu_el2_e2h_is_set(vcpu) && vcpu_el2_tge_is_set(vcpu)))

		__mmu_config_restore(&config);
@@ -1313,19 +1316,29 @@ static bool par_check_s1_perm_fault(u64 par) 
		 !(par & SYS_PAR_EL1_S));

}



static bool par_check_s1_access_fault(u64 par)

{

	u8 fst = FIELD_GET(SYS_PAR_EL1_FST, par);



	return  ((fst & ESR_ELx_FSC_TYPE) == ESR_ELx_FSC_ACCESS &&

		 !(par & SYS_PAR_EL1_S));

}



void __kvm_at_s1e01(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)

{

	u64 par = __kvm_at_s1e01_fast(vcpu, op, vaddr);



	/*

	 * If PAR_EL1 reports that AT failed on a S1 permission fault, we

	 * know for sure that the PTW was able to walk the S1 tables and

	 * there's nothing else to do.

	 * If PAR_EL1 reports that AT failed on a S1 permission or access

	 * fault, we know for sure that the PTW was able to walk the S1

	 * tables and there's nothing else to do.

	 *

	 * If AT failed for any other reason, then we must walk the guest S1

	 * to emulate the instruction.

	 */

	if ((par & SYS_PAR_EL1_F) && !par_check_s1_perm_fault(par))

	if ((par & SYS_PAR_EL1_F) &&

	    !par_check_s1_perm_fault(par) &&

	    !par_check_s1_access_fault(par))

		par = handle_at_slow(vcpu, op, vaddr);



	vcpu_write_sys_reg(vcpu, par, PAR_EL1);