repository: /home/avi/kvm/linux-2.6
branch: (no branch)
commit e16d8ea8c006e1e74c2ee973bf8e5ef6010ef189
Author: Laurent Vivier <[EMAIL PROTECTED]>
Date: Thu Aug 23 16:33:11 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]>
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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