Commit 61380a7a authored by Janis Schoetterl-Glausch's avatar Janis Schoetterl-Glausch Committed by Christian Borntraeger
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KVM: s390: handle_tprot: Honor storage keys 



Use the access key operand to check for key protection when
translating guest addresses.
Since the translation code checks for accessing exceptions/error hvas,
we can remove the check here and simplify the control flow.
Keep checking if the memory is read-only even if such memslots are
currently not supported.

handle_tprot was the last user of guest_translate_address,
so remove it.

Signed-off-by: default avatarJanis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20220211182215.2730017-4-scgl@linux.ibm.com


Signed-off-by: default avatarChristian Borntraeger <borntraeger@linux.ibm.com>
parent e613d834

arch/s390/kvm/gaccess.c

+0 −9
Original line number Diff line number Diff line
@@ -1118,15 +1118,6 @@ int guest_translate_address_with_key(struct kvm_vcpu *vcpu, unsigned long gva, u 
				   access_key);

}



int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,

			    unsigned long *gpa, enum gacc_mode mode)

{

	u8 access_key = psw_bits(vcpu->arch.sie_block->gpsw).key;



	return guest_translate_address_with_key(vcpu, gva, ar, gpa, mode,

						access_key);

}



/**

 * check_gva_range - test a range of guest virtual addresses for accessibility

 * @vcpu: virtual cpu

arch/s390/kvm/gaccess.h

+0 −3
Original line number Diff line number Diff line
@@ -190,9 +190,6 @@ int guest_translate_address_with_key(struct kvm_vcpu *vcpu, unsigned long gva, u 
				     unsigned long *gpa, enum gacc_mode mode,

				     u8 access_key);



int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,

			    u8 ar, unsigned long *gpa, enum gacc_mode mode);



int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,

		    unsigned long length, enum gacc_mode mode, u8 access_key);

arch/s390/kvm/priv.c

+35 −31
Original line number Diff line number Diff line
@@ -1443,10 +1443,11 @@ int kvm_s390_handle_eb(struct kvm_vcpu *vcpu) 


static int handle_tprot(struct kvm_vcpu *vcpu)

{

	u64 address1, address2;

	unsigned long hva, gpa;

	int ret = 0, cc = 0;

	u64 address, operand2;

	unsigned long gpa;

	u8 access_key;

	bool writable;

	int ret, cc;

	u8 ar;



	vcpu->stat.instruction_tprot++;
@@ -1454,43 +1455,46 @@ static int handle_tprot(struct kvm_vcpu *vcpu) 
	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)

		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);



	kvm_s390_get_base_disp_sse(vcpu, &address1, &address2, &ar, NULL);

	kvm_s390_get_base_disp_sse(vcpu, &address, &operand2, &ar, NULL);

	access_key = (operand2 & 0xf0) >> 4;



	/* we only handle the Linux memory detection case:

	 * access key == 0

	 * everything else goes to userspace. */

	if (address2 & 0xf0)

		return -EOPNOTSUPP;

	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)

		ipte_lock(vcpu);

	ret = guest_translate_address(vcpu, address1, ar, &gpa, GACC_STORE);

	if (ret == PGM_PROTECTION) {



	ret = guest_translate_address_with_key(vcpu, address, ar, &gpa,

					       GACC_STORE, access_key);

	if (ret == 0) {

		gfn_to_hva_prot(vcpu->kvm, gpa_to_gfn(gpa), &writable);

	} else if (ret == PGM_PROTECTION) {

		writable = false;

		/* Write protected? Try again with read-only... */

		cc = 1;

		ret = guest_translate_address(vcpu, address1, ar, &gpa,

					      GACC_FETCH);

		ret = guest_translate_address_with_key(vcpu, address, ar, &gpa,

						       GACC_FETCH, access_key);

	}

	if (ret) {

		if (ret == PGM_ADDRESSING || ret == PGM_TRANSLATION_SPEC) {

			ret = kvm_s390_inject_program_int(vcpu, ret);

		} else if (ret > 0) {

	if (ret >= 0) {

		cc = -1;



		/* Fetching permitted; storing permitted */

		if (ret == 0 && writable)

			cc = 0;

		/* Fetching permitted; storing not permitted */

		else if (ret == 0 && !writable)

			cc = 1;

		/* Fetching not permitted; storing not permitted */

		else if (ret == PGM_PROTECTION)

			cc = 2;

		/* Translation not available */

			kvm_s390_set_psw_cc(vcpu, 3);

		else if (ret != PGM_ADDRESSING && ret != PGM_TRANSLATION_SPEC)

			cc = 3;



		if (cc != -1) {

			kvm_s390_set_psw_cc(vcpu, cc);

			ret = 0;

		} else {

			ret = kvm_s390_inject_program_int(vcpu, ret);

		}

		goto out_unlock;

	}



	hva = gfn_to_hva_prot(vcpu->kvm, gpa_to_gfn(gpa), &writable);

	if (kvm_is_error_hva(hva)) {

		ret = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

	} else {

		if (!writable)

			cc = 1;		/* Write not permitted ==> read-only */

		kvm_s390_set_psw_cc(vcpu, cc);

		/* Note: CC2 only occurs for storage keys (not supported yet) */

	}

out_unlock:

	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)

		ipte_unlock(vcpu);

	return ret;