Re: [PATCH v12 08/20] KVM: pfncache: allow a cache to be activated with a fixed (userspace) HVA

[Sean Christopherson <seanjc@google.com>]

On Wed, Feb 14, 2024, Paul Durrant wrote:
> On 07/02/2024 04:03, Sean Christopherson wrote:
> > +s390 folks (question on kvm_is_error_gpa() for ya)
> > But!  kvm_is_error_gpa() already exists, and it very, very sneakily does a memslot
> > lookup and checks for a valid HVA.
> > 
> > s390 people, any objection to renaming kvm_is_error_gpa() to something like
> > kvm_gpa_has_memslot() or kvm_gpa_is_in_memslot()?  s390 is the only code that
> > uses the existing helper.
> > 
> > That would both to free up the name to pair with kvm_is_error_hva(), and would
> > make it obvious what the helper does; I was quite surprised that "error" means
> > "is covered by a valid memslot".
> > 
> 
> Seemingly no response to this; I'll define a local helper rather than
> re-working the open-coded tests to check against INVALID_GPA. This can then
> be trivially replaced if need be.

How about we force a decision with a patch?  This should be easy enough to slot
in, and I would be quite surprised if s390 is overly attached to kvm_is_error_gpa().

From: Sean Christopherson <seanjc@google.com>
Date: Wed, 14 Feb 2024 08:05:49 -0800
Subject: [PATCH] KVM: s390: Refactor kvm_is_error_gpa() into
 kvm_is_gpa_in_memslot()

Rename kvm_is_error_gpa() to kvm_is_gpa_in_memslot() and invert the
polarity accordingly in order to (a) free up kvm_is_error_gpa() to match
with kvm_is_error_{hva,page}(), and (b) to make it more obvious that the
helper is doing a memslot lookup, i.e. not simply checking for INVALID_GPA.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/s390/kvm/diag.c     |  2 +-
 arch/s390/kvm/gaccess.c  | 14 +++++++-------
 arch/s390/kvm/kvm-s390.c |  4 ++--
 arch/s390/kvm/priv.c     |  4 ++--
 arch/s390/kvm/sigp.c     |  2 +-
 include/linux/kvm_host.h |  4 ++--
 6 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index 3c65b8258ae6..2a32438e09ce 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -102,7 +102,7 @@ static int __diag_page_ref_service(struct kvm_vcpu *vcpu)
 		    parm.token_addr & 7 || parm.zarch != 0x8000000000000000ULL)
 			return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 
-		if (kvm_is_error_gpa(vcpu->kvm, parm.token_addr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, parm.token_addr))
 			return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 
 		vcpu->arch.pfault_token = parm.token_addr;
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 5bfcc50c1a68..415c99649e43 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -664,7 +664,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 	case ASCE_TYPE_REGION1:	{
 		union region1_table_entry rfte;
 
-		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 			return PGM_ADDRESSING;
 		if (deref_table(vcpu->kvm, ptr, &rfte.val))
 			return -EFAULT;
@@ -682,7 +682,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 	case ASCE_TYPE_REGION2: {
 		union region2_table_entry rste;
 
-		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 			return PGM_ADDRESSING;
 		if (deref_table(vcpu->kvm, ptr, &rste.val))
 			return -EFAULT;
@@ -700,7 +700,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 	case ASCE_TYPE_REGION3: {
 		union region3_table_entry rtte;
 
-		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 			return PGM_ADDRESSING;
 		if (deref_table(vcpu->kvm, ptr, &rtte.val))
 			return -EFAULT;
@@ -728,7 +728,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 	case ASCE_TYPE_SEGMENT: {
 		union segment_table_entry ste;
 
-		if (kvm_is_error_gpa(vcpu->kvm, ptr))
+		if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 			return PGM_ADDRESSING;
 		if (deref_table(vcpu->kvm, ptr, &ste.val))
 			return -EFAULT;
@@ -748,7 +748,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 		ptr = ste.fc0.pto * (PAGE_SIZE / 2) + vaddr.px * 8;
 	}
 	}
-	if (kvm_is_error_gpa(vcpu->kvm, ptr))
+	if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr))
 		return PGM_ADDRESSING;
 	if (deref_table(vcpu->kvm, ptr, &pte.val))
 		return -EFAULT;
@@ -770,7 +770,7 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
 		*prot = PROT_TYPE_IEP;
 		return PGM_PROTECTION;
 	}
-	if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
+	if (!kvm_is_gpa_in_memslot(vcpu->kvm, raddr.addr))
 		return PGM_ADDRESSING;
 	*gpa = raddr.addr;
 	return 0;
@@ -957,7 +957,7 @@ static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
 				return rc;
 		} else {
 			gpa = kvm_s390_real_to_abs(vcpu, ga);
-			if (kvm_is_error_gpa(vcpu->kvm, gpa)) {
+			if (!kvm_is_gpa_in_memslot(vcpu->kvm, gpa)) {
 				rc = PGM_ADDRESSING;
 				prot = PROT_NONE;
 			}
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index ea63ac769889..3e5a1d7aa81a 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2878,7 +2878,7 @@ static int kvm_s390_vm_mem_op_abs(struct kvm *kvm, struct kvm_s390_mem_op *mop)
 
 	srcu_idx = srcu_read_lock(&kvm->srcu);
 
-	if (kvm_is_error_gpa(kvm, mop->gaddr)) {
+	if (!kvm_is_gpa_in_memslot(kvm, mop->gaddr)) {
 		r = PGM_ADDRESSING;
 		goto out_unlock;
 	}
@@ -2940,7 +2940,7 @@ static int kvm_s390_vm_mem_op_cmpxchg(struct kvm *kvm, struct kvm_s390_mem_op *m
 
 	srcu_idx = srcu_read_lock(&kvm->srcu);
 
-	if (kvm_is_error_gpa(kvm, mop->gaddr)) {
+	if (!kvm_is_gpa_in_memslot(kvm, mop->gaddr)) {
 		r = PGM_ADDRESSING;
 		goto out_unlock;
 	}
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index f875a404a0a0..1be19cc9d73c 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -149,7 +149,7 @@ static int handle_set_prefix(struct kvm_vcpu *vcpu)
 	 * first page, since address is 8k aligned and memory pieces are always
 	 * at least 1MB aligned and have at least a size of 1MB.
 	 */
-	if (kvm_is_error_gpa(vcpu->kvm, address))
+	if (!kvm_is_gpa_in_memslot(vcpu->kvm, address))
 		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 
 	kvm_s390_set_prefix(vcpu, address);
@@ -464,7 +464,7 @@ static int handle_test_block(struct kvm_vcpu *vcpu)
 		return kvm_s390_inject_prog_irq(vcpu, &vcpu->arch.pgm);
 	addr = kvm_s390_real_to_abs(vcpu, addr);
 
-	if (kvm_is_error_gpa(vcpu->kvm, addr))
+	if (!kvm_is_gpa_in_memslot(vcpu->kvm, addr))
 		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 	/*
 	 * We don't expect errors on modern systems, and do not care
diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
index d9696b530064..55c34cb35428 100644
--- a/arch/s390/kvm/sigp.c
+++ b/arch/s390/kvm/sigp.c
@@ -172,7 +172,7 @@ static int __sigp_set_prefix(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
 	 * first page, since address is 8k aligned and memory pieces are always
 	 * at least 1MB aligned and have at least a size of 1MB.
 	 */
-	if (kvm_is_error_gpa(vcpu->kvm, irq.u.prefix.address)) {
+	if (!kvm_is_gpa_in_memslot(vcpu->kvm, irq.u.prefix.address)) {
 		*reg &= 0xffffffff00000000UL;
 		*reg |= SIGP_STATUS_INVALID_PARAMETER;
 		return SIGP_CC_STATUS_STORED;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7e7fd25b09b3..d175b64488ec 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1788,11 +1788,11 @@ static inline hpa_t pfn_to_hpa(kvm_pfn_t pfn)
 	return (hpa_t)pfn << PAGE_SHIFT;
 }
 
-static inline bool kvm_is_error_gpa(struct kvm *kvm, gpa_t gpa)
+static inline bool kvm_is_gpa_in_memslot(struct kvm *kvm, gpa_t gpa)
 {
 	unsigned long hva = gfn_to_hva(kvm, gpa_to_gfn(gpa));
 
-	return kvm_is_error_hva(hva);
+	return !kvm_is_error_hva(hva);
 }
 
 enum kvm_stat_kind {

base-commit: 687d8f4c3dea0758afd748968d91288220bbe7e3
--