[PATCH -V3 3/4] powerpc/kvm: Contiguous memory allocator based RMA allocation
Aneesh Kumar K.V
aneesh.kumar at linux.vnet.ibm.com
Wed Jul 3 01:29:55 EST 2013
Alexander Graf <agraf at suse.de> writes:
> On 07/02/2013 07:45 AM, Aneesh Kumar K.V wrote:
>> From: "Aneesh Kumar K.V"<aneesh.kumar at linux.vnet.ibm.com>
>>
>> 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 at samba.org>
>> Signed-off-by: Aneesh Kumar K.V<aneesh.kumar at linux.vnet.ibm.com>
>> ---
.... snip ....
>> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
>> index 550f592..55c8519 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;
>
> Is this really what we want? User space may want to use an RMA on POWER7
> systems, no?
IIUC they will use virtual real mode area (VRMA) and not RMA
>
>> +
>> + 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 4b865c5..8cd0dae 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)
>
> Please split the linar removal bits out into a separate patch :).
>
>
That was the way I had in the earlier patchset. That will cause a bisect
build break, because we consider warnings as error and we hit warning
of unused function.
I also realized that linear alloc functions are nearby and mostly fall
in the same hunk. Hence folded it back.
-aneesh
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