From 621358455ae043ab39bc3481f13b101bd6016c8d Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 1 May 2007 11:32:28 +0300 Subject: [PATCH] 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: Avi Kivity --- drivers/kvm/vmx.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index 9ebb18d07bde..49cadd31120b 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -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);