From b666a4b697397f8492dc11a2a1877557d3e0af56 Mon Sep 17 00:00:00 2001 From: Marc Orr Date: Tue, 6 Nov 2018 14:53:56 -0800 Subject: kvm: x86: Dynamically allocate guest_fpu Previously, the guest_fpu field was embedded in the kvm_vcpu_arch struct. Unfortunately, the field is quite large, (e.g., 4352 bytes on my current setup). This bloats the kvm_vcpu_arch struct for x86 into an order 3 memory allocation, which can become a problem on overcommitted machines. Thus, this patch moves the fpu state outside of the kvm_vcpu_arch struct. With this patch applied, the kvm_vcpu_arch struct is reduced to 15168 bytes for vmx on my setup when building the kernel with kvmconfig. Suggested-by: Dave Hansen Signed-off-by: Marc Orr Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/x86/kvm/svm.c') diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 0762e81e0498..e4f18a305ef6 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2125,6 +2125,13 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id) goto out; } + svm->vcpu.arch.guest_fpu = kmem_cache_zalloc(x86_fpu_cache, GFP_KERNEL); + if (!svm->vcpu.arch.guest_fpu) { + printk(KERN_ERR "kvm: failed to allocate vcpu's fpu\n"); + err = -ENOMEM; + goto free_partial_svm; + } + err = kvm_vcpu_init(&svm->vcpu, kvm, id); if (err) goto free_svm; @@ -2184,6 +2191,8 @@ free_page1: uninit: kvm_vcpu_uninit(&svm->vcpu); free_svm: + kmem_cache_free(x86_fpu_cache, svm->vcpu.arch.guest_fpu); +free_partial_svm: kmem_cache_free(kvm_vcpu_cache, svm); out: return ERR_PTR(err); @@ -2213,6 +2222,7 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu) __free_page(virt_to_page(svm->nested.hsave)); __free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER); kvm_vcpu_uninit(vcpu); + kmem_cache_free(x86_fpu_cache, svm->vcpu.arch.guest_fpu); kmem_cache_free(kvm_vcpu_cache, svm); } -- cgit v1.2.3