powerpc/kvm: Contiguous memory allocator based RMA allocation

Older version of power architecture use Real Mode Offset register and Real Mode Limit
Selector for mapping guest Real Mode Area. The guest RMA should be physically
contigous since we use the range when address translation is not enabled.

This patch switch RMA allocation code to use contigous memory allocator. The patch
also remove the the linear allocator which not used any more

Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

2 files changed, 58 insertions, 136 deletions

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 2efa9dde741..2b95c45e17d 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1511,10 +1511,10 @@ static inline int lpcr_rmls(unsigned long rma_size)
 
 static int kvm_rma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
-	struct kvmppc_linear_info *ri = vma->vm_file->private_data;
 	struct page *page;
+	struct kvm_rma_info *ri = vma->vm_file->private_data;
 
-	if (vmf->pgoff >= ri->npages)
+	if (vmf->pgoff >= kvm_rma_pages)
 		return VM_FAULT_SIGBUS;
 
 	page = pfn_to_page(ri->base_pfn + vmf->pgoff);
@@ -1536,7 +1536,7 @@ static int kvm_rma_mmap(struct file *file, struct vm_area_struct *vma)
 
 static int kvm_rma_release(struct inode *inode, struct file *filp)
 {
-	struct kvmppc_linear_info *ri = filp->private_data;
+	struct kvm_rma_info *ri = filp->private_data;
 
 	kvm_release_rma(ri);
 	return 0;
@@ -1549,8 +1549,17 @@ static const struct file_operations kvm_rma_fops = {
 
 long kvm_vm_ioctl_allocate_rma(struct kvm *kvm, struct kvm_allocate_rma *ret)
 {
-	struct kvmppc_linear_info *ri;
 	long fd;
+	struct kvm_rma_info *ri;
+	/*
+	 * Only do this on PPC970 in HV mode
+	 */
+	if (!cpu_has_feature(CPU_FTR_HVMODE) ||
+	    !cpu_has_feature(CPU_FTR_ARCH_201))
+		return -EINVAL;
+
+	if (!kvm_rma_pages)
+		return -EINVAL;
 
 	ri = kvm_alloc_rma();
 	if (!ri)
@@ -1560,7 +1569,7 @@ long kvm_vm_ioctl_allocate_rma(struct kvm *kvm, struct kvm_allocate_rma *ret)
 	if (fd < 0)
 		kvm_release_rma(ri);
 
-	ret->rma_size = ri->npages << PAGE_SHIFT;
+	ret->rma_size = kvm_rma_pages << PAGE_SHIFT;
 	return fd;
 }
 
@@ -1725,7 +1734,7 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
 {
 	int err = 0;
 	struct kvm *kvm = vcpu->kvm;
-	struct kvmppc_linear_info *ri = NULL;
+	struct kvm_rma_info *ri = NULL;
 	unsigned long hva;
 	struct kvm_memory_slot *memslot;
 	struct vm_area_struct *vma;
@@ -1803,7 +1812,7 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
 
 	} else {
 		/* Set up to use an RMO region */
-		rma_size = ri->npages;
+		rma_size = kvm_rma_pages;
 		if (rma_size > memslot->npages)
 			rma_size = memslot->npages;
 		rma_size <<= PAGE_SHIFT;
@@ -1831,14 +1840,14 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
 			/* POWER7 */
 			lpcr &= ~(LPCR_VPM0 | LPCR_VRMA_L);
 			lpcr |= rmls << LPCR_RMLS_SH;
-			kvm->arch.rmor = kvm->arch.rma->base_pfn << PAGE_SHIFT;
+			kvm->arch.rmor = ri->base_pfn << PAGE_SHIFT;
 		}
 		kvm->arch.lpcr = lpcr;
 		pr_info("KVM: Using RMO at %lx size %lx (LPCR = %lx)\n",
 			ri->base_pfn << PAGE_SHIFT, rma_size, lpcr);
 
 		/* Initialize phys addrs of pages in RMO */
-		npages = ri->npages;
+		npages = kvm_rma_pages;
 		porder = __ilog2(npages);
 		physp = memslot->arch.slot_phys;
 		if (physp) {
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 4b865c55333..8cd0daebb82 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -21,13 +21,6 @@
 #include <asm/kvm_book3s.h>
 
 #include "book3s_hv_cma.h"
-
-#define KVM_LINEAR_RMA		0
-#define KVM_LINEAR_HPT		1
-
-static void __init kvm_linear_init_one(ulong size, int count, int type);
-static struct kvmppc_linear_info *kvm_alloc_linear(int type);
-static void kvm_release_linear(struct kvmppc_linear_info *ri);
 /*
  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  * should be power of 2.
@@ -37,19 +30,17 @@ static void kvm_release_linear(struct kvmppc_linear_info *ri);
  * By default we reserve 5% of memory for hash pagetable allocation.
  */
 static unsigned long kvm_cma_resv_ratio = 5;
-
-/*************** RMA *************/
-
 /*
- * This maintains a list of RMAs (real mode areas) for KVM guests to use.
+ * We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area.
  * Each RMA has to be physically contiguous and of a size that the
  * hardware supports.  PPC970 and POWER7 support 64MB, 128MB and 256MB,
  * and other larger sizes.  Since we are unlikely to be allocate that
  * much physically contiguous memory after the system is up and running,
- * we preallocate a set of RMAs in early boot for KVM to use.
+ * we preallocate a set of RMAs in early boot using CMA.
+ * should be power of 2.
  */
-static unsigned long kvm_rma_size = 64 << 20;	/* 64MB */
-static unsigned long kvm_rma_count;
+unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;	/* 128MB */
+EXPORT_SYMBOL_GPL(kvm_rma_pages);
 
 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
    Assumes POWER7 or PPC970. */
@@ -79,35 +70,50 @@ static inline int lpcr_rmls(unsigned long rma_size)
 
 static int __init early_parse_rma_size(char *p)
 {
-	if (!p)
-		return 1;
+	unsigned long kvm_rma_size;
 
+	pr_debug("%s(%s)\n", __func__, p);
+	if (!p)
+		return -EINVAL;
 	kvm_rma_size = memparse(p, &p);
-
+	/*
+	 * Check that the requested size is one supported in hardware
+	 */
+	if (lpcr_rmls(kvm_rma_size) < 0) {
+		pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
+		return -EINVAL;
+	}
+	kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
 	return 0;
 }
 early_param("kvm_rma_size", early_parse_rma_size);
 
-static int __init early_parse_rma_count(char *p)
+struct kvm_rma_info *kvm_alloc_rma()
 {
-	if (!p)
-		return 1;
-
-	kvm_rma_count = simple_strtoul(p, NULL, 0);
-
-	return 0;
-}
-early_param("kvm_rma_count", early_parse_rma_count);
-
-struct kvmppc_linear_info *kvm_alloc_rma(void)
-{
-	return kvm_alloc_linear(KVM_LINEAR_RMA);
+	struct page *page;
+	struct kvm_rma_info *ri;
+
+	ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
+	if (!ri)
+		return NULL;
+	page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
+	if (!page)
+		goto err_out;
+	atomic_set(&ri->use_count, 1);
+	ri->base_pfn = page_to_pfn(page);
+	return ri;
+err_out:
+	kfree(ri);
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 
-void kvm_release_rma(struct kvmppc_linear_info *ri)
+void kvm_release_rma(struct kvm_rma_info *ri)
 {
-	kvm_release_linear(ri);
+	if (atomic_dec_and_test(&ri->use_count)) {
+		kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
+		kfree(ri);
+	}
 }
 EXPORT_SYMBOL_GPL(kvm_release_rma);
 
@@ -137,101 +143,6 @@ void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 }
 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 
-/*************** generic *************/
-
-static LIST_HEAD(free_linears);
-static DEFINE_SPINLOCK(linear_lock);
-
-static void __init kvm_linear_init_one(ulong size, int count, int type)
-{
-	unsigned long i;
-	unsigned long j, npages;
-	void *linear;
-	struct page *pg;
-	const char *typestr;
-	struct kvmppc_linear_info *linear_info;
-
-	if (!count)
-		return;
-
-	typestr = (type == KVM_LINEAR_RMA) ? "RMA" : "HPT";
-
-	npages = size >> PAGE_SHIFT;
-	linear_info = alloc_bootmem(count * sizeof(struct kvmppc_linear_info));
-	for (i = 0; i < count; ++i) {
-		linear = alloc_bootmem_align(size, size);
-		pr_debug("Allocated KVM %s at %p (%ld MB)\n", typestr, linear,
-			 size >> 20);
-		linear_info[i].base_virt = linear;
-		linear_info[i].base_pfn = __pa(linear) >> PAGE_SHIFT;
-		linear_info[i].npages = npages;
-		linear_info[i].type = type;
-		list_add_tail(&linear_info[i].list, &free_linears);
-		atomic_set(&linear_info[i].use_count, 0);
-
-		pg = pfn_to_page(linear_info[i].base_pfn);
-		for (j = 0; j < npages; ++j) {
-			atomic_inc(&pg->_count);
-			++pg;
-		}
-	}
-}
-
-static struct kvmppc_linear_info *kvm_alloc_linear(int type)
-{
-	struct kvmppc_linear_info *ri, *ret;
-
-	ret = NULL;
-	spin_lock(&linear_lock);
-	list_for_each_entry(ri, &free_linears, list) {
-		if (ri->type != type)
-			continue;
-
-		list_del(&ri->list);
-		atomic_inc(&ri->use_count);
-		memset(ri->base_virt, 0, ri->npages << PAGE_SHIFT);
-		ret = ri;
-		break;
-	}
-	spin_unlock(&linear_lock);
-	return ret;
-}
-
-static void kvm_release_linear(struct kvmppc_linear_info *ri)
-{
-	if (atomic_dec_and_test(&ri->use_count)) {
-		spin_lock(&linear_lock);
-		list_add_tail(&ri->list, &free_linears);
-		spin_unlock(&linear_lock);
-
-	}
-}
-
-/*
- * Called at boot time while the bootmem allocator is active,
- * to allocate contiguous physical memory for the hash page
- * tables for guests.
- */
-void __init kvm_linear_init(void)
-{
-	/* RMA */
-	/* Only do this on PPC970 in HV mode */
-	if (!cpu_has_feature(CPU_FTR_HVMODE) ||
-	    !cpu_has_feature(CPU_FTR_ARCH_201))
-		return;
-
-	if (!kvm_rma_size || !kvm_rma_count)
-		return;
-
-	/* Check that the requested size is one supported in hardware */
-	if (lpcr_rmls(kvm_rma_size) < 0) {
-		pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
-		return;
-	}
-
-	kvm_linear_init_one(kvm_rma_size, kvm_rma_count, KVM_LINEAR_RMA);
-}
-
 /**
  * kvm_cma_reserve() - reserve area for kvm hash pagetable
  *
@@ -265,6 +176,8 @@ void __init kvm_cma_reserve(void)
 			align_size = __rounddown_pow_of_two(selected_size);
 		else
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
+
+		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
 		kvm_cma_declare_contiguous(selected_size, align_size);
 	}
 }