ANDROID: KVM: arm64: iommu: DABT handler callback

Replace the 'host_mmio_dabt_handler' hook in kvm_iommu_ops with
an equivalent callback in the new pkvm_iommu_ops. The generic portion
of the code finds the IOMMU device at the faulted address and invokes
the callback on it.

Bug: 190463801
Change-Id: I0ca008c3e1ae0ec12a259fa4ddac1aee65aaac5c
Signed-off-by: David Brazdil <dbrazdil@google.com>
(cherry picked from commit 5df451f35e)
Signed-off-by: Mostafa Saleh <smostafa@google.com>

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

@@ -29,6 +29,14 @@ struct pkvm_iommu_ops {
 	int (*suspend)(struct pkvm_iommu *dev);
 	int (*resume)(struct pkvm_iommu *dev);
 
+	/*
+	 * Host data abort handler callback. Called with host lock held.
+	 * Returns true if the data abort has been handled.
+	 */
+	bool (*host_dabt_handler)(struct pkvm_iommu *dev,
+				  struct kvm_cpu_context *host_ctxt,
+				  u32 esr, size_t off);
+
 	/* Amount of memory allocated per-device for use by the driver. */
 	size_t data_size;
 };
@@ -53,6 +61,8 @@ int __pkvm_iommu_pm_notify(unsigned long dev_id,
 			   enum pkvm_iommu_pm_event event);
 int pkvm_iommu_host_stage2_adjust_range(phys_addr_t addr, phys_addr_t *start,
 					phys_addr_t *end);
+bool pkvm_iommu_host_dabt_handler(struct kvm_cpu_context *host_ctxt, u32 esr,
+				  phys_addr_t fault_pa);
 
 struct kvm_iommu_ops {
 	int (*init)(void);

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

@@ -11,6 +11,7 @@
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_pkvm.h>
 
+#include <hyp/adjust_pc.h>
 #include <nvhe/iommu.h>
 #include <nvhe/mm.h>
 
@@ -358,3 +359,24 @@ int pkvm_iommu_host_stage2_adjust_range(phys_addr_t addr, phys_addr_t *start,
 	*end = new_end;
 	return 0;
 }
+
+bool pkvm_iommu_host_dabt_handler(struct kvm_cpu_context *host_ctxt, u32 esr,
+				  phys_addr_t pa)
+{
+	struct pkvm_iommu *dev;
+
+	assert_host_component_locked();
+
+	list_for_each_entry(dev, &iommu_list, list) {
+		if (pa < dev->pa || pa >= dev->pa + dev->size)
+			continue;
+
+		if (!dev->powered || !dev->ops->host_dabt_handler ||
+		    !dev->ops->host_dabt_handler(dev, host_ctxt, esr, pa - dev->pa))
+			return false;
+
+		kvm_skip_host_instr();
+		return true;
+	}
+	return false;
+}

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

@@ -630,9 +630,9 @@ static int host_stage2_idmap(u64 addr)
 	enum kvm_pgtable_prot prot;
 	int ret;
 
-	prot = is_memory ? PKVM_HOST_MEM_PROT : PKVM_HOST_MMIO_PROT;
+	hyp_assert_lock_held(&host_mmu.lock);
 
-	host_lock_component();
+	prot = is_memory ? PKVM_HOST_MEM_PROT : PKVM_HOST_MMIO_PROT;
 	/*
 	 * Adjust against IOMMU devices first. host_stage2_adjust_range() should
 	 * be called last for proper alignment.
@@ -641,18 +641,14 @@ static int host_stage2_idmap(u64 addr)
 		ret = pkvm_iommu_host_stage2_adjust_range(addr, &range.start,
 							  &range.end);
 		if (ret)
-			goto unlock;
+			return ret;
 	}
 
 	ret = host_stage2_adjust_range(addr, &range);
 	if (ret)
-		goto unlock;
+		return ret;
 
-	ret = host_stage2_idmap_locked(range.start, range.end - range.start, prot);
-unlock:
-	host_unlock_component();
-
-	return ret;
+	return host_stage2_idmap_locked(range.start, range.end - range.start, prot);
 }
 
 static void host_inject_abort(struct kvm_cpu_context *host_ctxt)
@@ -699,26 +695,6 @@ static void host_inject_abort(struct kvm_cpu_context *host_ctxt)
 	write_sysreg_el2(spsr, SYS_SPSR);
 }
 
-static int host_mmio_dabt_handler(struct kvm_cpu_context *host_ctxt, u32 esr,
-				  phys_addr_t addr)
-{
-	bool wnr = esr & ESR_ELx_WNR;
-	unsigned int len = BIT((esr & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT);
-	int rd = (esr & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT;
-	bool handled = false;
-
-	if (kvm_iommu_ops.host_mmio_dabt_handler) {
-		handled = kvm_iommu_ops.host_mmio_dabt_handler(host_ctxt, addr,
-							       len, wnr, rd);
-	}
-
-	if (!handled)
-		return -EPERM;
-
-	kvm_skip_host_instr();
-	return 0;
-}
-
 static bool is_dabt(u64 esr)
 {
 	return ESR_ELx_EC(esr) == ESR_ELx_EC_DABT_LOW;
@@ -736,14 +712,19 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
 	addr = (fault.hpfar_el2 & HPFAR_MASK) << 8;
 	addr |= fault.far_el2 & FAR_MASK;
 
-	/* See if any subsystem can handle this abort. */
-	if (is_dabt(esr) && !addr_is_memory(addr))
-		ret = host_mmio_dabt_handler(host_ctxt, esr, addr);
+	host_lock_component();
+
+	/* Check if an IOMMU device can handle the DABT. */
+	if (is_dabt(esr) && !addr_is_memory(addr) &&
+	    pkvm_iommu_host_dabt_handler(host_ctxt, esr, addr))
+		ret = 0;
 
 	/* If not handled, attempt to map the page. */
 	if (ret == -EPERM)
 		ret = host_stage2_idmap(addr);
 
+	host_unlock_component();
+
 	if (ret == -EPERM)
 		host_inject_abort(host_ctxt);
 	else