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)
> 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)
> {
>
--
Thanks,
David / dhildenb
