[SVM] Make sure that the WP bit is always set in CR0 when running SVM guests.

This is necessary to be sure that the shadow mode code can always detect
writes to guest page tables.

This should fix Windows restore from hibernation on SVM platforms.

Signed-off-by: Tom Woller <thomas.woller@amd.com>

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 455bdac52e3f336d6ce01ddf1106596d02c78fce..f2a8659136de7fce5221df129921743eddaad082 100644 (file)
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1441,7 +1441,7 @@ static int svm_set_cr0(unsigned long value)
     /* We don't want to lose PG.  ET is reserved and should be always be 1*/
     paging_enabled = svm_paging_enabled(v);
     value |= X86_CR0_ET;
-    vmcb->cr0 = value | X86_CR0_PG;
+    vmcb->cr0 = value | X86_CR0_PG | X86_CR0_WP;
     v->arch.hvm_svm.cpu_shadow_cr0 = value;
 
     /* TS cleared? Then initialise FPU now. */
@@ -2094,7 +2094,7 @@ static int svm_do_vmmcall_reset_to_realmode(struct vcpu *v,
     vmcb->tsc_offset = 0;
 
     /* VMCB State */
-    vmcb->cr0 = X86_CR0_ET | X86_CR0_PG;
+    vmcb->cr0 = X86_CR0_ET | X86_CR0_PG | X86_CR0_WP;
     v->arch.hvm_svm.cpu_shadow_cr0 = X86_CR0_ET;
 
     vmcb->cr2 = 0;

diff --git a/xen/arch/x86/hvm/svm/vmcb.c b/xen/arch/x86/hvm/svm/vmcb.c
index fb246ae0ad88e87144423b731bcab4343233dae8..f00372440efe0b561307a95c507d7039d94d64b7 100644 (file)
--- a/xen/arch/x86/hvm/svm/vmcb.c
+++ b/xen/arch/x86/hvm/svm/vmcb.c
@@ -197,6 +197,7 @@ static int construct_vmcb(struct vcpu *v)
     /* Guest CR0. */
     vmcb->cr0 = read_cr0();
     arch_svm->cpu_shadow_cr0 = vmcb->cr0 & ~(X86_CR0_PG | X86_CR0_TS);
+    vmcb->cr0 |= X86_CR0_WP;
 
     /* Guest CR4. */
     arch_svm->cpu_shadow_cr4 =