Mailing List Archive

# HG changeset patch
# User Keir Fraser <keir@xen.org>
# Date 1297013950 0
# Node ID 3e47933c9623b594ca9b44d845acef6e51bd2f4c
# Parent 0b16e1d60871aaeb94ca1e8e83a41b54b4579f07
hvm amd: Fix 32bit guest VM save/restore issues associated with SYSENTER MSRs

This patch turn-on SYSENTER MSRs interception for 32bit guest VMs on
AMD CPUs. With it, hvm_svm.guest_sysenter_xx fields always contain the
canonical version of SYSENTER MSRs and are used in guest save/restore.
The data fields in VMCB save area are updated as necessary.

Reported-by: James Harper <james.harper@bendigoit.com.au>
Signed-off-by: Wei Huang <wei.huang2@amd.com>
xen-unstable changeset: 22873:186162762071
xen-unstable date: Sun Feb 06 17:03:09 2011 +0000
---
xen/arch/x86/hvm/svm/svm.c | 41 ++++++++++++++++++++++++++---------------
1 files changed, 26 insertions(+), 15 deletions(-)

diff -r 0b16e1d60871 -r 3e47933c9623 xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c Wed Jan 26 09:05:53 2011 +0000
+++ b/xen/arch/x86/hvm/svm/svm.c Sun Feb 06 17:39:10 2011 +0000
@@ -251,10 +251,11 @@ static int svm_vmcb_restore(struct vcpu
hvm_update_guest_cr(v, 2);
hvm_update_guest_cr(v, 4);

- v->arch.hvm_svm.guest_sysenter_cs = c->sysenter_cs;
- v->arch.hvm_svm.guest_sysenter_esp = c->sysenter_esp;
- v->arch.hvm_svm.guest_sysenter_eip = c->sysenter_eip;
-
+ /* Load sysenter MSRs into both VMCB save area and VCPU fields. */
+ vmcb->sysenter_cs = v->arch.hvm_svm.guest_sysenter_cs = c->sysenter_cs;
+ vmcb->sysenter_esp = v->arch.hvm_svm.guest_sysenter_esp = c->sysenter_esp;
+ vmcb->sysenter_eip = v->arch.hvm_svm.guest_sysenter_eip = c->sysenter_eip;
+
if ( paging_mode_hap(v->domain) )
{
vmcb->np_enable = 1;
@@ -449,14 +450,6 @@ static void svm_update_guest_efer(struct
vmcb->efer = (v->arch.hvm_vcpu.guest_efer | EFER_SVME) & ~EFER_LME;
if ( lma )
vmcb->efer |= EFER_LME;
-
- /*
- * In legacy mode (EFER.LMA=0) we natively support SYSENTER/SYSEXIT with
- * no need for MSR intercepts. When 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_sync_vmcb(struct vcpu *v)
@@ -1099,6 +1092,21 @@ static int svm_msr_write_intercept(struc
u32 ecx = regs->ecx;
struct vcpu *v = current;
struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
+ int sync = 0;
+
+ switch ( ecx )
+ {
+ case MSR_IA32_SYSENTER_CS:
+ case MSR_IA32_SYSENTER_ESP:
+ case MSR_IA32_SYSENTER_EIP:
+ sync = 1;
+ break;
+ default:
+ break;
+ }
+
+ if ( sync )
+ svm_sync_vmcb(v);

msr_content = (u32)regs->eax | ((u64)regs->edx << 32);

@@ -1110,13 +1118,13 @@ static int svm_msr_write_intercept(struc
goto gpf;

case MSR_IA32_SYSENTER_CS:
- v->arch.hvm_svm.guest_sysenter_cs = msr_content;
+ vmcb->sysenter_cs = v->arch.hvm_svm.guest_sysenter_cs = msr_content;
break;
case MSR_IA32_SYSENTER_ESP:
- v->arch.hvm_svm.guest_sysenter_esp = msr_content;
+ vmcb->sysenter_esp = v->arch.hvm_svm.guest_sysenter_esp = msr_content;
break;
case MSR_IA32_SYSENTER_EIP:
- v->arch.hvm_svm.guest_sysenter_eip = msr_content;
+ vmcb->sysenter_eip = v->arch.hvm_svm.guest_sysenter_eip = msr_content;
break;

case MSR_IA32_DEBUGCTLMSR:
@@ -1163,6 +1171,9 @@ static int svm_msr_write_intercept(struc
}
break;
}
+
+ if ( sync )
+ svm_vmload(vmcb);

return X86EMUL_OKAY;


_______________________________________________
Xen-changelog mailing list
Xen-changelog@lists.xensource.com
http://lists.xensource.com/xen-changelog