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 <[email protected]> --- 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
