On 16.05.2018 11:43, David Hildenbrand wrote:
> On 15.05.2018 13:37, Marc Orr wrote:
>> The kvm struct has been bloating. For example, it's tens of kilo-bytes
>> for x86, which turns out to be a large amount of memory to allocate
>> contiguously via kzalloc. Thus, this patch does the following:
>> 1. Uses architecture-specific routines to allocat the kvm struct via
>> kzalloc for x86 and also for arm when has_tbe() is true.
>> 2. Introduces a baseline allocator for the kvm struct that uses valloc.
>> This allocator can be used by an architecture by defining the
>> __KVM_VALLOC_ARCH_VM macro before including include/linux/kvm_host.h.
>> 3. Finally, continue to default to kalloc for all other situations, as
>> many architectures have taken a dependence on kalloc.
>>
>> Signed-off-by: Marc Orr <marcorr@xxxxxxxxxx>
>> Change-Id: Ide392e51991142d1325e06351231ac685e11d820
>> ---
>> arch/arm/include/asm/kvm_host.h | 4 ++++
>> arch/arm64/include/asm/kvm_host.h | 4 ++++
>> arch/x86/kvm/svm.c | 4 ++--
>> arch/x86/kvm/vmx.c | 4 ++--
>> include/linux/kvm_host.h | 13 +++++++++++++
>> virt/kvm/arm/arm.c | 15 +++++++++++++++
>> 6 files changed, 40 insertions(+), 4 deletions(-)
>>
>
> I thought we verified that s390x is also not a problem. Any reason not
> to include it? (sorry if I am missing review comments from earlier
> versions but if there is a reason, it should go into the cover letter)
Christian did decide against it as our struct is quite small compared to
others.
See:
Message-ID: <2401fda4-f081-0693-bcb6-3538bcea7be1@xxxxxxxxxx>
>
>
>> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
>> index c7c28c885a19..f38fd60b4d4d 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -318,4 +318,8 @@ static inline bool kvm_arm_harden_branch_predictor(void)
>> static inline void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) {}
>> static inline void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) {}
>>
>> +#define __KVM_HAVE_ARCH_VM_ALLOC
>> +struct kvm *kvm_arch_alloc_vm(void);
>> +void kvm_arch_free_vm(struct kvm *kvm);
>> +
>> #endif /* __ARM_KVM_HOST_H__ */
>> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
>> index 469de8acd06f..358b1b4dcd92 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -455,4 +455,8 @@ static inline bool kvm_arm_harden_branch_predictor(void)
>> void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu);
>> void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu);
>>
>> +#define __KVM_HAVE_ARCH_VM_ALLOC
>> +struct kvm *kvm_arch_alloc_vm(void);
>> +void kvm_arch_free_vm(struct kvm *kvm);
>> +
>> #endif /* __ARM64_KVM_HOST_H__ */
>> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
>> index 1fc05e428aba..45b903ed3e5d 100644
>> --- a/arch/x86/kvm/svm.c
>> +++ b/arch/x86/kvm/svm.c
>> @@ -1849,13 +1849,13 @@ static void __unregister_enc_region_locked(struct kvm *kvm,
>>
>> static struct kvm *svm_vm_alloc(void)
>> {
>> - struct kvm_svm *kvm_svm = kzalloc(sizeof(struct kvm_svm), GFP_KERNEL);
>> + struct kvm_svm *kvm_svm = vzalloc(sizeof(struct kvm_svm));
>> return &kvm_svm->kvm;
>> }
>>
>> static void svm_vm_free(struct kvm *kvm)
>> {
>> - kfree(to_kvm_svm(kvm));
>> + vfree(to_kvm_svm(kvm));
>> }
>>
>> static void sev_vm_destroy(struct kvm *kvm)
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 3f1696570b41..ee85ba887db6 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -9936,13 +9936,13 @@ STACK_FRAME_NON_STANDARD(vmx_vcpu_run);
>>
>> static struct kvm *vmx_vm_alloc(void)
>> {
>> - struct kvm_vmx *kvm_vmx = kzalloc(sizeof(struct kvm_vmx), GFP_KERNEL);
>> + struct kvm_vmx *kvm_vmx = vzalloc(sizeof(struct kvm_vmx));
>> return &kvm_vmx->kvm;
>> }
>>
>> static void vmx_vm_free(struct kvm *kvm)
>> {
>> - kfree(to_kvm_vmx(kvm));
>> + vfree(to_kvm_vmx(kvm));
>> }
>>
>> static void vmx_switch_vmcs(struct kvm_vcpu *vcpu, struct loaded_vmcs *vmcs)
>> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
>> index 6d6e79c59e68..e3134283321a 100644
>> --- a/include/linux/kvm_host.h
>> +++ b/include/linux/kvm_host.h
>> @@ -19,6 +19,7 @@
>> #include <linux/preempt.h>
>> #include <linux/msi.h>
>> #include <linux/slab.h>
>> +#include <linux/vmalloc.h>
>> #include <linux/rcupdate.h>
>> #include <linux/ratelimit.h>
>> #include <linux/err.h>
>> @@ -808,6 +809,17 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu);
>> int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu);
>>
>> #ifndef __KVM_HAVE_ARCH_VM_ALLOC
>> +#ifdef __KVM_VALLOC_ARCH_VM
>> +static inline struct kvm *kvm_arch_alloc_vm(void)
>> +{
>> + return vzalloc(sizeof(struct kvm));
>> +}
>> +
>> +static inline void kvm_arch_free_vm(struct kvm *kvm)
>> +{
>> + vfree(kvm);
>> +}
>> +#else
>> static inline struct kvm *kvm_arch_alloc_vm(void)
>> {
>> return kzalloc(sizeof(struct kvm), GFP_KERNEL);
>> @@ -818,6 +830,7 @@ static inline void kvm_arch_free_vm(struct kvm *kvm)
>> kfree(kvm);
>> }
>> #endif
>> +#endif
>>
>> #ifdef __KVM_HAVE_ARCH_NONCOHERENT_DMA
>> void kvm_arch_register_noncoherent_dma(struct kvm *kvm);
>> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
>> index a4c1b76240df..ee96f18f852a 100644
>> --- a/virt/kvm/arm/arm.c
>> +++ b/virt/kvm/arm/arm.c
>> @@ -249,6 +249,21 @@ long kvm_arch_dev_ioctl(struct file *filp,
>> return -EINVAL;
>> }
>>
>> +struct kvm *kvm_arch_alloc_vm(void)
>> +{
>> + if (!has_vhe())
>> + return kzalloc(sizeof(struct kvm), GFP_KERNEL);
>> +
>> + return vzalloc(sizeof(struct kvm));
>> +}
>> +
>> +void kvm_arch_free_vm(struct kvm *kvm)
>> +{
>> + if (!has_vhe())
>> + kfree(kvm);
>> + else
>> + vfree(kvm);
>> +}
>>
>> struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
>> {
>>
>
>
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