From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: [PATCH][SVM][UPDATE] Lazy MSR save/restore Date: Sat, 28 Apr 2007 19:57:49 -0500 Message-ID: <4633ED8D.4000806@us.ibm.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------030600020504090902080309" To: kvm-devel , Avi Kivity Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org This is a multi-part message in MIME format. --------------030600020504090902080309 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Third time's a charm, right? :-) Regards, Anthony Liguori --------------030600020504090902080309 Content-Type: text/x-patch; name="svm-lazy-msrs.diff" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="svm-lazy-msrs.diff" From: Anthony Liguori Subject: [PATCH][SVM] Only save/restore MSRs when needed We only have to save/restore MSR_GS_BASE on every VMEXIT. The rest can be saved/restored when we leave the VCPU. Since we don't emulate the DEBUGCTL MSRs and the guest cannot write to them, we don't have to worry about saving/restoring them at all. Signed-off-by: Anthony Liguori Index: kernel/drivers/kvm/svm.c =================================================================== --- kernel.orig/drivers/kvm/svm.c 2007-04-27 21:05:24.000000000 -0500 +++ kernel/drivers/kvm/svm.c 2007-04-28 19:39:05.840763552 -0500 @@ -522,8 +522,6 @@ control->msrpm_base_pa = msrpm_base; control->tsc_offset = 0; control->int_ctl = V_INTR_MASKING_MASK; - if (svm_has(SVM_FEATURE_LBRV)) - control->lbr_ctl = 1ULL; init_seg(&save->es); init_seg(&save->ss); @@ -611,7 +609,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu) { - int cpu; + int cpu, i; cpu = get_cpu(); if (unlikely(cpu != vcpu->cpu)) { @@ -626,10 +624,18 @@ vcpu->svm->vmcb->control.tsc_offset += delta; vcpu->cpu = cpu; } + + for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) + rdmsrl(host_save_user_msrs[i], vcpu->svm->host_user_msrs[i]); } static void svm_vcpu_put(struct kvm_vcpu *vcpu) { + int i; + + for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) + wrmsrl(host_save_user_msrs[i], vcpu->svm->host_user_msrs[i]); + rdtscll(vcpu->host_tsc); put_cpu(); } @@ -815,18 +821,16 @@ static void load_host_msrs(struct kvm_vcpu *vcpu) { - int i; - - for ( i = 0; i < NR_HOST_SAVE_MSRS; i++) - wrmsrl(host_save_msrs[i], vcpu->svm->host_msrs[i]); +#ifdef CONFIG_X86_64 + wrmsrl(MSR_GS_BASE, vcpu->svm->host_gs_base); +#endif } static void save_host_msrs(struct kvm_vcpu *vcpu) { - int i; - - for ( i = 0; i < NR_HOST_SAVE_MSRS; i++) - rdmsrl(host_save_msrs[i], vcpu->svm->host_msrs[i]); +#ifdef CONFIG_X86_64 + rdmsrl(MSR_GS_BASE, vcpu->svm->host_gs_base); +#endif } static void new_asid(struct kvm_vcpu *vcpu, struct svm_cpu_data *svm_data) Index: kernel/drivers/kvm/kvm_svm.h =================================================================== --- kernel.orig/drivers/kvm/kvm_svm.h 2007-04-27 18:42:10.000000000 -0500 +++ kernel/drivers/kvm/kvm_svm.h 2007-04-28 19:39:15.239334752 -0500 @@ -9,17 +9,15 @@ #include "svm.h" #include "kvm.h" -static const u32 host_save_msrs[] = { +static const u32 host_save_user_msrs[] = { #ifdef CONFIG_X86_64 MSR_STAR, MSR_LSTAR, MSR_CSTAR, MSR_SYSCALL_MASK, MSR_KERNEL_GS_BASE, - MSR_FS_BASE, MSR_GS_BASE, + MSR_FS_BASE, #endif MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP, - MSR_IA32_DEBUGCTLMSR, /*MSR_IA32_LASTBRANCHFROMIP, - MSR_IA32_LASTBRANCHTOIP, MSR_IA32_LASTINTFROMIP,MSR_IA32_LASTINTTOIP,*/ }; -#define NR_HOST_SAVE_MSRS ARRAY_SIZE(host_save_msrs) +#define NR_HOST_SAVE_USER_MSRS ARRAY_SIZE(host_save_user_msrs) #define NUM_DB_REGS 4 struct vcpu_svm { @@ -32,7 +30,8 @@ u64 next_rip; - u64 host_msrs[NR_HOST_SAVE_MSRS]; + u64 host_user_msrs[NR_HOST_SAVE_USER_MSRS]; + u64 host_gs_base; unsigned long host_cr2; unsigned long host_db_regs[NUM_DB_REGS]; unsigned long host_dr6; --------------030600020504090902080309 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ --------------030600020504090902080309 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ kvm-devel mailing list kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org https://lists.sourceforge.net/lists/listinfo/kvm-devel --------------030600020504090902080309--