From 7f11aa4b2b1ff6f47da772aa4e532a891dc13c70 Mon Sep 17 00:00:00 2001 From: Sergey Dyasli Date: Thu, 23 Feb 2017 09:33:26 +0000 Subject: [PATCH] x86/vmx: optimize vmx_read/write_guest_msr() Replace linear scan with vmx_find_msr(). This way the time complexity of searching for required MSR reduces from linear to logarithmic. Signed-off-by: Sergey Dyasli Acked-by: Kevin Tian Reviewed-by: Jan Beulich --- xen/arch/x86/hvm/vmx/vmcs.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-) diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c index ba78d8ad0a..03e68ad2a2 100644 --- a/xen/arch/x86/hvm/vmx/vmcs.c +++ b/xen/arch/x86/hvm/vmx/vmcs.c @@ -1358,17 +1358,12 @@ struct vmx_msr_entry *vmx_find_msr(u32 msr, int type) int vmx_read_guest_msr(u32 msr, u64 *val) { - struct vcpu *curr = current; - unsigned int i, msr_count = curr->arch.hvm_vmx.msr_count; - const struct vmx_msr_entry *msr_area = curr->arch.hvm_vmx.msr_area; + struct vmx_msr_entry *ent; - for ( i = 0; i < msr_count; i++ ) + if ( (ent = vmx_find_msr(msr, VMX_GUEST_MSR)) != NULL ) { - if ( msr_area[i].index == msr ) - { - *val = msr_area[i].data; - return 0; - } + *val = ent->data; + return 0; } return -ESRCH; @@ -1376,17 +1371,12 @@ int vmx_read_guest_msr(u32 msr, u64 *val) int vmx_write_guest_msr(u32 msr, u64 val) { - struct vcpu *curr = current; - unsigned int i, msr_count = curr->arch.hvm_vmx.msr_count; - struct vmx_msr_entry *msr_area = curr->arch.hvm_vmx.msr_area; + struct vmx_msr_entry *ent; - for ( i = 0; i < msr_count; i++ ) + if ( (ent = vmx_find_msr(msr, VMX_GUEST_MSR)) != NULL ) { - if ( msr_area[i].index == msr ) - { - msr_area[i].data = val; - return 0; - } + ent->data = val; + return 0; } return -ESRCH; -- 2.30.2