In instruction/mmio emulation cases, if the target write memroy
is SPP protected, "fake" an vmexit to userspace to let application
handle it.
Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
---
arch/x86/kvm/x86.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4b033a39d6c3..e3999a3ab911 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5788,6 +5788,37 @@ static const struct read_write_emulator_ops write_emultor = {
.write = true,
};
+static bool is_emulator_spp_protected(struct kvm_vcpu *vcpu,
+ gpa_t gpa,
+ unsigned int bytes)
+{
+ gfn_t gfn, gfn_start, gfn_end;
+ struct kvm *kvm = vcpu->kvm;
+ struct kvm_memory_slot *slot;
+ u32 *access;
+
+ if (!kvm->arch.spp_active)
+ return false;
+
+ gfn_start = gpa_to_gfn(gpa);
+ gfn_end = gpa_to_gfn(gpa + bytes);
+ for (gfn = gfn_start; gfn <= gfn_end; gfn++) {
+ slot = gfn_to_memslot(kvm, gfn);
+ if (slot) {
+ access = gfn_to_subpage_wp_info(slot, gfn);
+ if (access && *access != FULL_SPP_ACCESS) {
+ vcpu->run->exit_reason = KVM_EXIT_SPP;
+ vcpu->run->spp.addr = gfn;
+ vcpu->run->spp.insn_len =
+ kvm_x86_ops.get_insn_len(vcpu);
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
static int emulator_read_write_onepage(unsigned long addr, void *val,
unsigned int bytes,
struct x86_exception *exception,
@@ -5817,6 +5848,9 @@ static int emulator_read_write_onepage(unsigned long addr, void *val,
return X86EMUL_PROPAGATE_FAULT;
}
+ if (write && is_emulator_spp_protected(vcpu, gpa, bytes))
+ return X86EMUL_UNHANDLEABLE;
+
if (!ret && ops->read_write_emulate(vcpu, gpa, val, bytes))
return X86EMUL_CONTINUE;
@@ -6963,6 +6997,9 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
return 1;
if (r == EMULATION_FAILED) {
+ if (vcpu->run->exit_reason == KVM_EXIT_SPP)
+ return 0;
+
if (reexecute_instruction(vcpu, cr2_or_gpa, write_fault_to_spt,
emulation_type))
return 1;
--
2.17.2
