[RFC PATCH v1 03/10] KVM: s390: handle_tprot: Honor storage keys

[Janis Schoetterl-Glausch]

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: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx>
Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
---
 arch/s390/kvm/gaccess.c |  9 ------
 arch/s390/kvm/gaccess.h |  3 --
 arch/s390/kvm/priv.c    | 66 ++++++++++++++++++++++-------------------
 3 files changed, 35 insertions(+), 43 deletions(-)

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 92ab96d55504..efe33cda38b6 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -1104,15 +1104,6 @@ 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)
-{
-	char 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
diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 3df432702cd6..0d4416178bb6 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -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,
 				     char 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,
 		    char access_key);
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 417154b314a6..7c68f893545c 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -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;
+	char 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) {
-			/* Translation not available */
-			kvm_s390_set_psw_cc(vcpu, 3);
+	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 */
+		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;
-- 
2.32.0