Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=152d3f2f246ce3c2a0cf2fc6c2214663cd99aa83
Commit:     152d3f2f246ce3c2a0cf2fc6c2214663cd99aa83
Parent:     d39dba54ce71ab3234c387219b175dc36d37f85a
Author:     Laurent Vivier <[EMAIL PROTECTED]>
AuthorDate: Thu Aug 23 16:33:11 2007 +0200
Committer:  Avi Kivity <[EMAIL PROTECTED]>
CommitDate: Sat Oct 13 10:18:24 2007 +0200

    KVM: VMX: Split segments reload in vmx_load_host_state()
    
    vmx_load_host_state() bundles fs, gs, ldt, and tss reloading into
    one in the hope that it is infrequent. With smp guests, fs reloading is
    frequent due to fs being used by threads.
    
    Unbundle the reloads so reduce expensive gs reloads.
    
    Signed-off-by: Laurent Vivier <[EMAIL PROTECTED]>
    Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
---
 drivers/kvm/vmx.c |   22 ++++++++++++----------
 1 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index b400668..d63e82e 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -54,7 +54,8 @@ struct vcpu_vmx {
        struct {
                int           loaded;
                u16           fs_sel, gs_sel, ldt_sel;
-               int           fs_gs_ldt_reload_needed;
+               int           gs_ldt_reload_needed;
+               int           fs_reload_needed;
        }host_state;
 
 };
@@ -353,20 +354,21 @@ static void vmx_save_host_state(struct vcpu_vmx *vmx)
         * allow segment selectors with cpl > 0 or ti == 1.
         */
        vmx->host_state.ldt_sel = read_ldt();
-       vmx->host_state.fs_gs_ldt_reload_needed = vmx->host_state.ldt_sel;
+       vmx->host_state.gs_ldt_reload_needed = vmx->host_state.ldt_sel;
        vmx->host_state.fs_sel = read_fs();
-       if (!(vmx->host_state.fs_sel & 7))
+       if (!(vmx->host_state.fs_sel & 7)) {
                vmcs_write16(HOST_FS_SELECTOR, vmx->host_state.fs_sel);
-       else {
+               vmx->host_state.fs_reload_needed = 0;
+       } else {
                vmcs_write16(HOST_FS_SELECTOR, 0);
-               vmx->host_state.fs_gs_ldt_reload_needed = 1;
+               vmx->host_state.fs_reload_needed = 1;
        }
        vmx->host_state.gs_sel = read_gs();
        if (!(vmx->host_state.gs_sel & 7))
                vmcs_write16(HOST_GS_SELECTOR, vmx->host_state.gs_sel);
        else {
                vmcs_write16(HOST_GS_SELECTOR, 0);
-               vmx->host_state.fs_gs_ldt_reload_needed = 1;
+               vmx->host_state.gs_ldt_reload_needed = 1;
        }
 
 #ifdef CONFIG_X86_64
@@ -396,9 +398,10 @@ static void vmx_load_host_state(struct vcpu_vmx *vmx)
                return;
 
        vmx->host_state.loaded = 0;
-       if (vmx->host_state.fs_gs_ldt_reload_needed) {
-               load_ldt(vmx->host_state.ldt_sel);
+       if (vmx->host_state.fs_reload_needed)
                load_fs(vmx->host_state.fs_sel);
+       if (vmx->host_state.gs_ldt_reload_needed) {
+               load_ldt(vmx->host_state.ldt_sel);
                /*
                 * If we have to reload gs, we must take care to
                 * preserve our gs base.
@@ -409,9 +412,8 @@ static void vmx_load_host_state(struct vcpu_vmx *vmx)
                wrmsrl(MSR_GS_BASE, vmcs_readl(HOST_GS_BASE));
 #endif
                local_irq_restore(flags);
-
-               reload_tss();
        }
+       reload_tss();
        save_msrs(vmx->guest_msrs, vmx->save_nmsrs);
        load_msrs(vmx->host_msrs, vmx->save_nmsrs);
        if (msr_efer_need_save_restore(vmx))
-
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