[PATCH -V3 3/4] powerpc/kvm: Contiguous memory allocator based RMA allocation
Alexander Graf
agraf at suse.de
Wed Jul 3 01:32:08 EST 2013
On 07/02/2013 05:29 PM, Aneesh Kumar K.V wrote:
> 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
Then I suppose we should at least update the comment a bit further down
the patch that indicates that on POWER7 systems we do support a real
RMA. I can't really think of any reason why user space would want to use
RMA over VRMA.
>
>>> +
>>> + 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.
Fair enough :)
Alex
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