# HG changeset patch
# User Christoph Egger <Christoph.Egger@xxxxxxx>
# Date 1305549102 -3600
# Node ID 776b0c3e6544ea91f8b7e94214c9e4b390337003
# Parent edcf8fc77b64955236a697691b223662354461b5
nestedsvm: fix fpu context switch
Two different vmcb's are used to run l1 guest and l2 guest.
When host xen switches physical FPU to a different cpu while
l1 or l2 guest is running we need to sync CR0.TS bit in the
other vmcb.
Signed-off-by: Christoph Egger <Christoph.Egger@xxxxxxx>
Reviewed-by: Uwe Dannowski <Uwe.Dannowski@xxxxxxx>
Reviewed-by: Wei Huang <Wei.Huang2@xxxxxxx>
---
diff -r edcf8fc77b64 -r 776b0c3e6544 xen/arch/x86/hvm/svm/nestedsvm.c
--- a/xen/arch/x86/hvm/svm/nestedsvm.c Mon May 16 13:29:24 2011 +0100
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c Mon May 16 13:31:42 2011 +0100
@@ -165,6 +165,45 @@
return 0;
}
+static uint64_t nestedsvm_fpu_vmentry(uint64_t n1cr0,
+ struct vmcb_struct *vvmcb,
+ struct vmcb_struct *n1vmcb, struct vmcb_struct *n2vmcb)
+{
+ uint64_t vcr0;
+
+ vcr0 = vvmcb->_cr0;
+ if ( !(n1cr0 & X86_CR0_TS) && (n1vmcb->_cr0 & X86_CR0_TS) ) {
+ /* svm_fpu_leave() run while l1 guest was running.
+ * Sync FPU state with l2 guest.
+ */
+ vcr0 |= X86_CR0_TS;
+ n2vmcb->_exception_intercepts |= (1U << TRAP_no_device);
+ } else if ( !(vcr0 & X86_CR0_TS) && (n2vmcb->_cr0 & X86_CR0_TS) ) {
+ /* svm_fpu_enter() run while l1 guest was running.
+ * Sync FPU state with l2 guest. */
+ vcr0 &= ~X86_CR0_TS;
+ n2vmcb->_exception_intercepts &= ~(1U << TRAP_no_device);
+ }
+
+ return vcr0;
+}
+
+static void nestedsvm_fpu_vmexit(struct vmcb_struct *n1vmcb,
+ struct vmcb_struct *n2vmcb, uint64_t n1cr0, uint64_t guest_cr0)
+{
+ if ( !(guest_cr0 & X86_CR0_TS) && (n2vmcb->_cr0 & X86_CR0_TS) ) {
+ /* svm_fpu_leave() run while l2 guest was running.
+ * Sync FPU state with l1 guest. */
+ n1vmcb->_cr0 |= X86_CR0_TS;
+ n1vmcb->_exception_intercepts |= (1U << TRAP_no_device);
+ } else if ( !(n1cr0 & X86_CR0_TS) && (n1vmcb->_cr0 & X86_CR0_TS) ) {
+ /* svm_fpu_enter() run while l2 guest was running.
+ * Sync FPU state with l1 guest. */
+ n1vmcb->_cr0 &= ~X86_CR0_TS;
+ n1vmcb->_exception_intercepts &= ~(1U << TRAP_no_device);
+ }
+}
+
static int nsvm_vcpu_hostsave(struct vcpu *v, unsigned int inst_len)
{
struct nestedsvm *svm = &vcpu_nestedsvm(v);
@@ -176,6 +215,13 @@
n1vmcb->rip += inst_len;
+ /* Save shadowed values. This ensures that the l1 guest
+ * cannot override them to break out. */
+ n1vmcb->_efer = v->arch.hvm_vcpu.guest_efer;
+ n1vmcb->_cr0 = v->arch.hvm_vcpu.guest_cr[0];
+ n1vmcb->_cr2 = v->arch.hvm_vcpu.guest_cr[2];
+ n1vmcb->_cr4 = v->arch.hvm_vcpu.guest_cr[4];
+
/* Remember the host interrupt flag */
svm->ns_hostflags.fields.rflagsif =
(n1vmcb->rflags & X86_EFLAGS_IF) ? 1 : 0;
@@ -186,6 +232,7 @@
int nsvm_vcpu_hostrestore(struct vcpu *v, struct cpu_user_regs *regs)
{
struct nestedvcpu *nv = &vcpu_nestedhvm(v);
+ struct nestedsvm *svm = &vcpu_nestedsvm(v);
struct vmcb_struct *n1vmcb, *n2vmcb;
int rc;
@@ -215,11 +262,14 @@
gdprintk(XENLOG_ERR, "hvm_set_cr4 failed, rc: %u\n", rc);
/* CR0 */
+ nestedsvm_fpu_vmexit(n1vmcb, n2vmcb,
+ svm->ns_cr0, v->arch.hvm_vcpu.guest_cr[0]);
v->arch.hvm_vcpu.guest_cr[0] = n1vmcb->_cr0 | X86_CR0_PE;
n1vmcb->rflags &= ~X86_EFLAGS_VM;
rc = hvm_set_cr0(n1vmcb->_cr0 | X86_CR0_PE);
if (rc != X86EMUL_OKAY)
gdprintk(XENLOG_ERR, "hvm_set_cr0 failed, rc: %u\n", rc);
+ svm->ns_cr0 = v->arch.hvm_vcpu.guest_cr[0];
/* CR2 */
v->arch.hvm_vcpu.guest_cr[2] = n1vmcb->_cr2;
@@ -336,6 +386,7 @@
struct vmcb_struct *ns_vmcb, *n1vmcb, *n2vmcb;
bool_t vcleanbits_valid;
int rc;
+ uint64_t cr0;
ns_vmcb = nv->nv_vvmcx;
n1vmcb = nv->nv_n1vmcx;
@@ -470,8 +521,10 @@
gdprintk(XENLOG_ERR, "hvm_set_cr4 failed, rc: %u\n", rc);
/* CR0 */
+ svm->ns_cr0 = v->arch.hvm_vcpu.guest_cr[0];
+ cr0 = nestedsvm_fpu_vmentry(svm->ns_cr0, ns_vmcb, n1vmcb, n2vmcb);
v->arch.hvm_vcpu.guest_cr[0] = ns_vmcb->_cr0;
- rc = hvm_set_cr0(ns_vmcb->_cr0);
+ rc = hvm_set_cr0(cr0);
if (rc != X86EMUL_OKAY)
gdprintk(XENLOG_ERR, "hvm_set_cr0 failed, rc: %u\n", rc);
diff -r edcf8fc77b64 -r 776b0c3e6544 xen/include/asm-x86/hvm/svm/nestedsvm.h
--- a/xen/include/asm-x86/hvm/svm/nestedsvm.h Mon May 16 13:29:24 2011 +0100
+++ b/xen/include/asm-x86/hvm/svm/nestedsvm.h Mon May 16 13:31:42 2011 +0100
@@ -56,6 +56,9 @@
/* Shadow io permission map */
unsigned long *ns_iomap;
+ uint64_t ns_cr0; /* Cached guest_cr[0] of l1 guest while l2 guest runs.
+ * Needed to handle FPU context switching */
+
/* Cache guest cr3/host cr3 the guest sets up for the l2 guest.
* Used by Shadow-on-Shadow and Nested-on-Nested.
* ns_vmcb_guestcr3: in l2 guest physical address space and points to
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