Commit e920de85 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: vmx: compute need to reload FS/GS/LDT on demand 



Remove fs_reload_needed and gs_ldt_reload_needed from host_state
and instead compute whether we need to reload various state at
the time we actually do the reload.  The state that is tracked
by the *_reload_needed variables is not any more volatile than
the trackers themselves.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent fd1ec772

arch/x86/kvm/vmx.c

+5 −13
Original line number Diff line number Diff line
@@ -824,8 +824,6 @@ struct vcpu_vmx { 
#ifdef CONFIG_X86_64

		u16           ds_sel, es_sel;

#endif

		int           gs_ldt_reload_needed;

		int           fs_reload_needed;

	} host_state;

	struct {

		int vm86_active;
@@ -2681,7 +2679,6 @@ static void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) 
	 * allow segment selectors with cpl > 0 or ti == 1.

	 */

	vmx->host_state.ldt_sel = kvm_read_ldt();

	vmx->host_state.gs_ldt_reload_needed = vmx->host_state.ldt_sel;



#ifdef CONFIG_X86_64

	savesegment(ds, vmx->host_state.ds_sel);
@@ -2711,20 +2708,15 @@ static void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) 
#endif



	vmx->host_state.fs_sel = fs_sel;

	if (!(fs_sel & 7)) {

	if (!(fs_sel & 7))

		vmcs_write16(HOST_FS_SELECTOR, fs_sel);

		vmx->host_state.fs_reload_needed = 0;

	} else {

	else

		vmcs_write16(HOST_FS_SELECTOR, 0);

		vmx->host_state.fs_reload_needed = 1;

	}

	vmx->host_state.gs_sel = gs_sel;

	if (!(gs_sel & 7))

		vmcs_write16(HOST_GS_SELECTOR, gs_sel);

	else {

	else

		vmcs_write16(HOST_GS_SELECTOR, 0);

		vmx->host_state.gs_ldt_reload_needed = 1;

	}



	vmcs_writel(HOST_FS_BASE, fs_base);

	vmcs_writel(HOST_GS_BASE, gs_base);
@@ -2749,7 +2741,7 @@ static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx) 
	if (is_long_mode(&vmx->vcpu))

		rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);

#endif

	if (vmx->host_state.gs_ldt_reload_needed) {

	if (vmx->host_state.ldt_sel || (vmx->host_state.gs_sel & 7)) {

		kvm_load_ldt(vmx->host_state.ldt_sel);

#ifdef CONFIG_X86_64

		load_gs_index(vmx->host_state.gs_sel);
@@ -2757,7 +2749,7 @@ static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx) 
		loadsegment(gs, vmx->host_state.gs_sel);

#endif

	}

	if (vmx->host_state.fs_reload_needed)

	if (vmx->host_state.fs_sel & 7)

		loadsegment(fs, vmx->host_state.fs_sel);

#ifdef CONFIG_X86_64

	if (unlikely(vmx->host_state.ds_sel | vmx->host_state.es_sel)) {

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