Commit e4c7dfac authored by Oliver Upton's avatar Oliver Upton
Browse files

KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW 



Give the stage-2 walk similar treatment to stage-1: update the access
flag during the table walk and do so for any walk context.

Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Tested-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://msgid.link/20251124190158.177318-14-oupton@kernel.org


Signed-off-by: default avatarOliver Upton <oupton@kernel.org>
parent bff8aa21

arch/arm64/kvm/mmu.c

+5 −0
Original line number Diff line number Diff line
@@ -2012,6 +2012,11 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) 
		u32 esr;



		ret = kvm_walk_nested_s2(vcpu, fault_ipa, &nested_trans);

		if (ret == -EAGAIN) {

			ret = 1;

			goto out_unlock;

		}



		if (ret) {

			esr = kvm_s2_trans_esr(&nested_trans);

			kvm_inject_s2_fault(vcpu, esr);

arch/arm64/kvm/nested.c

+37 −7
Original line number Diff line number Diff line
@@ -130,6 +130,7 @@ struct s2_walk_info { 
	unsigned int	sl;

	unsigned int	t0sz;

	bool		be;

	bool		ha;

};



static u32 compute_fsc(int level, u32 fsc)
@@ -219,6 +220,20 @@ static int read_guest_s2_desc(struct kvm_vcpu *vcpu, phys_addr_t pa, u64 *desc, 
	return 0;

}



static int swap_guest_s2_desc(struct kvm_vcpu *vcpu, phys_addr_t pa, u64 old, u64 new,

			      struct s2_walk_info *wi)

{

	if (wi->be) {

		old = cpu_to_be64(old);

		new = cpu_to_be64(new);

	} else {

		old = cpu_to_le64(old);

		new = cpu_to_le64(new);

	}



	return __kvm_at_swap_desc(vcpu->kvm, pa, old, new);

}



/*

 * This is essentially a C-version of the pseudo code from the ARM ARM

 * AArch64.TranslationTableWalk  function.  I strongly recommend looking at
@@ -232,7 +247,7 @@ static int walk_nested_s2_pgd(struct kvm_vcpu *vcpu, phys_addr_t ipa, 
	int first_block_level, level, stride, input_size, base_lower_bound;

	phys_addr_t base_addr;

	unsigned int addr_top, addr_bottom;

	u64 desc;  /* page table entry */

	u64 desc, new_desc;  /* page table entry */

	int ret;

	phys_addr_t paddr;
@@ -281,6 +296,8 @@ static int walk_nested_s2_pgd(struct kvm_vcpu *vcpu, phys_addr_t ipa, 
		if (ret < 0)

			return ret;



		new_desc = desc;



		/* Check for valid descriptor at this point */

		if (!(desc & KVM_PTE_VALID)) {

			out->esr = compute_fsc(level, ESR_ELx_FSC_FAULT);
@@ -325,6 +342,17 @@ static int walk_nested_s2_pgd(struct kvm_vcpu *vcpu, phys_addr_t ipa, 
		return 1;

	}



	if (wi->ha)

		new_desc |= KVM_PTE_LEAF_ATTR_LO_S2_AF;



	if (new_desc != desc) {

		ret = swap_guest_s2_desc(vcpu, paddr, desc, new_desc, wi);

		if (ret)

			return ret;



		desc = new_desc;

	}



	if (!(desc & KVM_PTE_LEAF_ATTR_LO_S2_AF)) {

		out->esr = compute_fsc(level, ESR_ELx_FSC_ACCESS);

		out->desc = desc;
@@ -363,6 +391,8 @@ static void vtcr_to_walk_info(u64 vtcr, struct s2_walk_info *wi) 
	/* Global limit for now, should eventually be per-VM */

	wi->max_oa_bits = min(get_kvm_ipa_limit(),

			      ps_to_output_size(FIELD_GET(VTCR_EL2_PS_MASK, vtcr), false));



	wi->ha = vtcr & VTCR_EL2_HA;

}



int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa,