ANDROID: KVM: arm64: iommu: Return map error code

The driver already returns the error code which is ignored by the
hypercall, so return the error code in X0.
And don't return -ENOMEM as that is communicated by requests.

Bug: 401132481
Change-Id: I9479028f3c49c11aa3071bc24222027c5b4c1a85
Signed-off-by: Mostafa Saleh <smostafa@google.com>

arch/arm64/kvm/hyp/include/nvhe/iommu.h

@@ -23,7 +23,7 @@ int kvm_iommu_detach_dev(pkvm_handle_t iommu_id, pkvm_handle_t domain_id,
 			 u32 endpoint_id, u32 pasid);
 size_t kvm_iommu_map_pages(pkvm_handle_t domain_id,
 			   unsigned long iova, phys_addr_t paddr, size_t pgsize,
-			   size_t pgcount, int prot);
+			   size_t pgcount, int prot, unsigned long *mapped);
 size_t kvm_iommu_unmap_pages(pkvm_handle_t domain_id, unsigned long iova,
 			     size_t pgsize, size_t pgcount);
 phys_addr_t kvm_iommu_iova_to_phys(pkvm_handle_t domain_id, unsigned long iova);

arch/arm64/kvm/hyp/nvhe/hyp-main.c

@@ -1744,7 +1744,8 @@ static void handle___pkvm_host_iommu_detach_dev(struct kvm_cpu_context *host_ctx
 
 static void handle___pkvm_host_iommu_map_pages(struct kvm_cpu_context *host_ctxt)
 {
-	unsigned long ret;
+	int ret;
+	unsigned long mapped;
 	DECLARE_REG(pkvm_handle_t, domain, host_ctxt, 1);
 	DECLARE_REG(unsigned long, iova, host_ctxt, 2);
 	DECLARE_REG(phys_addr_t, paddr, host_ctxt, 3);
@@ -1753,8 +1754,9 @@ static void handle___pkvm_host_iommu_map_pages(struct kvm_cpu_context *host_ctxt
 	DECLARE_REG(unsigned int, prot, host_ctxt, 6);
 
 	ret = kvm_iommu_map_pages(domain, iova, paddr,
-				  pgsize, pgcount, prot);
-	hyp_reqs_smccc_encode(ret, host_ctxt, this_cpu_ptr(&host_hyp_reqs));
+				  pgsize, pgcount, prot, &mapped);
+	cpu_reg(host_ctxt, 0) = ret;
+	hyp_reqs_smccc_encode(mapped, host_ctxt, this_cpu_ptr(&host_hyp_reqs));
 }
 
 static void handle___pkvm_host_iommu_unmap_pages(struct kvm_cpu_context *host_ctxt)

arch/arm64/kvm/hyp/nvhe/iommu/iommu.c

@@ -464,29 +464,32 @@ out_unlock:
 
 size_t kvm_iommu_map_pages(pkvm_handle_t domain_id,
 			   unsigned long iova, phys_addr_t paddr, size_t pgsize,
-			   size_t pgcount, int prot)
+			   size_t pgcount, int prot, unsigned long *mapped)
 {
 	size_t size;
 	int ret;
 	size_t total_mapped = 0;
 	struct kvm_hyp_iommu_domain *domain;
 
+	*mapped = 0;
+
 	if (prot & ~IOMMU_PROT_MASK)
-		return 0;
+		return -EOPNOTSUPP;
 
 	if (__builtin_mul_overflow(pgsize, pgcount, &size) ||
 	    iova + size < iova || paddr + size < paddr)
-		return 0;
+		return -E2BIG;
 
 	domain = handle_to_domain(domain_id);
 	if (!domain || domain_get(domain))
-		return 0;
+		return -ENOENT;
 
 	ret = __pkvm_use_dma(paddr, size, __get_vcpu());
 	if (ret)
 		goto out_put_domain;
 
-	kvm_iommu_ops->map_pages(domain, iova, paddr, pgsize, pgcount, prot, &total_mapped);
+	ret = kvm_iommu_ops->map_pages(domain, iova, paddr, pgsize, pgcount,
+				       prot, &total_mapped);
 
 	pgcount -= total_mapped / pgsize;
 	/*
@@ -497,9 +500,12 @@ size_t kvm_iommu_map_pages(pkvm_handle_t domain_id,
 	if (pgcount)
 		__pkvm_unuse_dma(paddr + total_mapped, pgcount * pgsize, __get_vcpu());
 
+	*mapped = total_mapped;
+
 out_put_domain:
 	domain_put(domain);
-	return total_mapped;
+	/* Mask -ENOMEM, as it's passed as a request. */
+	return ret == -ENOMEM ? 0 : ret;
 }
 
 static inline void kvm_iommu_iotlb_sync(struct kvm_hyp_iommu_domain *domain,

arch/arm64/kvm/hyp/nvhe/iommu/pviommu.c

@@ -282,9 +282,9 @@ static bool pkvm_guest_iommu_map(struct pkvm_hyp_vcpu *hyp_vcpu, u64 *exit_code)
 			break;
 		}
 
-		mapped = kvm_iommu_map_pages(domain, iova, paddr,
-					     PAGE_SIZE, min(size, kvm_granule_size(level)) / PAGE_SIZE,
-					     __smccc_prot_linux(prot));
+		kvm_iommu_map_pages(domain, iova, paddr,
+				    PAGE_SIZE, min(size, kvm_granule_size(level)) / PAGE_SIZE,
+				    __smccc_prot_linux(prot), &mapped);
 		WARN_ON(__pkvm_unuse_dma(paddr, kvm_granule_size(level), hyp_vcpu));
 		if (!mapped) {
 			if (!__need_req(vcpu)) {