Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 62135845 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: Be more careful restoring fs on lightweight vmexit 



i386 wants fs for accessing the pda even on a lightweight exit, so ensure
we can always restore it.  This fixes a regression on i386 introduced by
the lightweight vmexit patch.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent a25f7e1f

drivers/kvm/vmx.c

+11 −11
Original line number Diff line number Diff line
@@ -1832,16 +1832,21 @@ static int vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
	 * Set host fs and gs selectors.  Unfortunately, 22.2.3 does not

	 * allow segment selectors with cpl > 0 or ti == 1.

	 */

	fs_sel = read_fs();

	gs_sel = read_gs();

	ldt_sel = read_ldt();

	fs_gs_ldt_reload_needed = (fs_sel & 7) | (gs_sel & 7) | ldt_sel;

	if (!fs_gs_ldt_reload_needed) {

	fs_gs_ldt_reload_needed = ldt_sel;

	fs_sel = read_fs();

	if (!(fs_sel & 7))

		vmcs_write16(HOST_FS_SELECTOR, fs_sel);

		vmcs_write16(HOST_GS_SELECTOR, gs_sel);

	} else {

	else {

		vmcs_write16(HOST_FS_SELECTOR, 0);

		fs_gs_ldt_reload_needed = 1;

	}

	gs_sel = read_gs();

	if (!(gs_sel & 7))

		vmcs_write16(HOST_GS_SELECTOR, gs_sel);

	else {

		vmcs_write16(HOST_GS_SELECTOR, 0);

		fs_gs_ldt_reload_needed = 1;

	}



#ifdef CONFIG_X86_64
@@ -2035,11 +2040,6 @@ static int vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) 
	}



out:

	/*

	 * Reload segment selectors ASAP. (it's needed for a functional

	 * kernel: x86 relies on having __KERNEL_PDA in %fs and x86_64

	 * relies on having 0 in %gs for the CPU PDA to work.)

	 */

	if (fs_gs_ldt_reload_needed) {

		load_ldt(ldt_sel);

		load_fs(fs_sel);