# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1246095213 -3600
# Node ID 49ae55a9c4429ea2ee34e7e723b99f7ad024a7b7
# Parent 43523102a8e9093acef4be9da8ec4ff4928ccea8
x86 svm: Make 32bit legacy guests boot again
Attached patch fixes a bug introduced in c/s 19648.
32bit legacy guests have the sysenter/sysexit instructions available.
Therefore, we have to disable intercepts for the sysenter MSRs or the
guest stucks in an infinite loop of #GPs, otherwise.
For guests in 64bit mode and 32bit compat mode, sysenter/sysexit
instructions aren't available. The sysenter MSRs have to be
intercepted to make the instruction emulation working.
Signed-off-by: Christoph Egger <Christoph.Egger@xxxxxxx>
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/arch/x86/hvm/svm/svm.c | 11 +++++++++-
xen/arch/x86/hvm/svm/vmcb.c | 40 +++++++++++++++++++++----------------
xen/include/asm-x86/hvm/svm/vmcb.h | 4 ++-
3 files changed, 36 insertions(+), 19 deletions(-)
diff -r 43523102a8e9 -r 49ae55a9c442 xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c Sat Jun 27 10:02:52 2009 +0100
+++ b/xen/arch/x86/hvm/svm/svm.c Sat Jun 27 10:33:33 2009 +0100
@@ -452,10 +452,19 @@ static void svm_update_guest_efer(struct
static void svm_update_guest_efer(struct vcpu *v)
{
struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
+ bool_t lma = v->arch.hvm_vcpu.guest_efer & EFER_LMA;
vmcb->efer = (v->arch.hvm_vcpu.guest_efer | EFER_SVME) & ~EFER_LME;
- if ( vmcb->efer & EFER_LMA )
+ if ( lma )
vmcb->efer |= EFER_LME;
+
+ /*
+ * In legacy mode (EFER.LMA=0) we natively support SYSENTER/SYSEXIT with
+ * no need for MSR intercepts. Ehen EFER.LMA=1 we must trap and emulate.
+ */
+ svm_intercept_msr(v, MSR_IA32_SYSENTER_CS, lma);
+ svm_intercept_msr(v, MSR_IA32_SYSENTER_ESP, lma);
+ svm_intercept_msr(v, MSR_IA32_SYSENTER_EIP, lma);
}
static void svm_flush_guest_tlbs(void)
diff -r 43523102a8e9 -r 49ae55a9c442 xen/arch/x86/hvm/svm/vmcb.c
--- a/xen/arch/x86/hvm/svm/vmcb.c Sat Jun 27 10:02:52 2009 +0100
+++ b/xen/arch/x86/hvm/svm/vmcb.c Sat Jun 27 10:33:33 2009 +0100
@@ -78,29 +78,34 @@ struct host_save_area *alloc_host_save_a
return hsa;
}
-void svm_disable_intercept_for_msr(struct vcpu *v, u32 msr)
+void svm_intercept_msr(struct vcpu *v, uint32_t msr, int enable)
{
unsigned long *msr_bitmap = v->arch.hvm_svm.msrpm;
+ unsigned long *msr_bit = NULL;
/*
* See AMD64 Programmers Manual, Vol 2, Section 15.10 (MSR-Bitmap Address).
*/
if ( msr <= 0x1fff )
- {
- __clear_bit(msr*2, msr_bitmap + 0x000/BYTES_PER_LONG);
- __clear_bit(msr*2+1, msr_bitmap + 0x000/BYTES_PER_LONG);
- }
+ msr_bit = msr_bitmap + 0x0000 / BYTES_PER_LONG;
else if ( (msr >= 0xc0000000) && (msr <= 0xc0001fff) )
- {
- msr &= 0x1fff;
- __clear_bit(msr*2, msr_bitmap + 0x800/BYTES_PER_LONG);
- __clear_bit(msr*2+1, msr_bitmap + 0x800/BYTES_PER_LONG);
- }
- else if ( (msr >= 0xc001000) && (msr <= 0xc0011fff) )
- {
- msr &= 0x1fff;
- __clear_bit(msr*2, msr_bitmap + 0x1000/BYTES_PER_LONG);
- __clear_bit(msr*2+1, msr_bitmap + 0x1000/BYTES_PER_LONG);
+ msr_bit = msr_bitmap + 0x0800 / BYTES_PER_LONG;
+ else if ( (msr >= 0xc0010000) && (msr <= 0xc0011fff) )
+ msr_bit = msr_bitmap + 0x1000 / BYTES_PER_LONG;
+
+ BUG_ON(msr_bit == NULL);
+
+ msr &= 0x1fff;
+
+ if ( enable )
+ {
+ __set_bit(msr * 2, msr_bit);
+ __set_bit(msr * 2 + 1, msr_bit);
+ }
+ else
+ {
+ __clear_bit(msr * 2, msr_bit);
+ __clear_bit(msr * 2 + 1, msr_bit);
}
}
@@ -165,8 +170,9 @@ static int construct_vmcb(struct vcpu *v
if ( opt_softtsc )
vmcb->general1_intercepts |= GENERAL1_INTERCEPT_RDTSC;
- /* Guest EFER: *must* contain SVME or VMRUN will fail. */
- vmcb->efer = EFER_SVME;
+ /* Guest EFER. */
+ v->arch.hvm_vcpu.guest_efer = 0;
+ hvm_update_guest_efer(v);
/* Guest segment limits. */
vmcb->cs.limit = ~0u;
diff -r 43523102a8e9 -r 49ae55a9c442 xen/include/asm-x86/hvm/svm/vmcb.h
--- a/xen/include/asm-x86/hvm/svm/vmcb.h Sat Jun 27 10:02:52 2009 +0100
+++ b/xen/include/asm-x86/hvm/svm/vmcb.h Sat Jun 27 10:33:33 2009 +0100
@@ -481,7 +481,9 @@ void svm_destroy_vmcb(struct vcpu *v);
void setup_vmcb_dump(void);
-void svm_disable_intercept_for_msr(struct vcpu *v, u32 msr);
+void svm_intercept_msr(struct vcpu *v, uint32_t msr, int enable);
+#define svm_disable_intercept_for_msr(v, msr) svm_intercept_msr((v), (msr), 0)
+#define svm_enable_intercept_for_msr(v, msr) svm_intercept_msr((v), (msr), 1)
#endif /* ASM_X86_HVM_SVM_VMCS_H__ */
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