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KVM: Be more careful restoring fs on lightweight vmexit

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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 <avi@qumranet.com>
This commit is contained in:
Avi Kivity 2007-05-01 11:32:28 +03:00
parent a25f7e1f8c
commit 621358455a
1 changed files with 11 additions and 11 deletions
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22
drivers/kvm/vmx.c
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@ -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);