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authorIngo Molnar <mingo@elte.hu>2007-03-11 13:52:33 +0100
committerAvi Kivity <avi@qumranet.com>2007-03-27 17:55:48 +0200
commit6d9658df07789a124e5c1f8677afcd7773439f3e (patch)
treead7b6c562c1d52f9794508c0e29ff18e73bc795e /drivers/kvm
parent6af11b9e827aac1d664ccd31e94f122c7698416b (diff)
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KVM: always reload segment selectors
failed VM entry on VMX might still change %fs or %gs, thus make sure that KVM always reloads the segment selectors. This is crutial on both x86 and x86_64: x86 has __KERNEL_PDA in %fs on which things like 'current' depends and x86_64 has 0 there and needs MSR_GS_BASE to work. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'drivers/kvm')
-rw-r--r--drivers/kvm/vmx.c37
1 files changed, 21 insertions, 16 deletions
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 25b2471..fbbf9d6 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1888,6 +1888,27 @@ again:
[cr2]"i"(offsetof(struct kvm_vcpu, cr2))
: "cc", "memory" );
+ /*
+ * 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);
+ /*
+ * If we have to reload gs, we must take care to
+ * preserve our gs base.
+ */
+ local_irq_disable();
+ load_gs(gs_sel);
+#ifdef CONFIG_X86_64
+ wrmsrl(MSR_GS_BASE, vmcs_readl(HOST_GS_BASE));
+#endif
+ local_irq_enable();
+
+ reload_tss();
+ }
++kvm_stat.exits;
save_msrs(vcpu->guest_msrs, NR_BAD_MSRS);
@@ -1905,22 +1926,6 @@ again:
kvm_run->exit_reason = vmcs_read32(VM_INSTRUCTION_ERROR);
r = 0;
} else {
- if (fs_gs_ldt_reload_needed) {
- load_ldt(ldt_sel);
- load_fs(fs_sel);
- /*
- * If we have to reload gs, we must take care to
- * preserve our gs base.
- */
- local_irq_disable();
- load_gs(gs_sel);
-#ifdef CONFIG_X86_64
- wrmsrl(MSR_GS_BASE, vmcs_readl(HOST_GS_BASE));
-#endif
- local_irq_enable();
-
- reload_tss();
- }
/*
* Profile KVM exit RIPs:
*/