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Message-Id: <20191106074504.14858-10-weijiang.yang@intel.com>
Date: Wed, 6 Nov 2019 15:45:04 +0800
From: Yang Weijiang <weijiang.yang@...el.com>
To: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
pbonzini@...hat.com, jmattson@...gle.com,
sean.j.christopherson@...el.com
Cc: yu.c.zhang@...ux.intel.com, alazar@...defender.com,
edwin.zhai@...el.com, Yang Weijiang <weijiang.yang@...el.com>
Subject: [PATCH v6 9/9] x86: spp: Add SPP protection check in emulation.
In instruction/mmio emulation cases, if the target write memroy
is SPP protected, exit to user-space to handle it as if it's
caused by SPP induced EPT violation due to guest write.
Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
---
arch/x86/kvm/x86.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fa114b5db672..71f5a8ae76cf 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5525,6 +5525,36 @@ 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, start_gfn, end_gfn;
+ struct kvm *kvm = vcpu->kvm;
+ struct kvm_memory_slot *slot;
+ u32 access;
+
+ if (!kvm->arch.spp_active)
+ return false;
+
+ start_gfn = gpa >> PAGE_SHIFT;
+ end_gfn = (gpa + bytes) >> PAGE_SHIFT;
+ for (gfn = start_gfn; gfn <= end_gfn; gfn++) {
+ slot = gfn_to_memslot(kvm, gfn);
+ if (slot) {
+ access = *gfn_to_subpage_wp_info(slot, gfn);
+ if (access != FULL_SPP_ACCESS) {
+ vcpu->run->exit_reason = KVM_EXIT_SPP;
+ vcpu->run->spp.addr = gfn;
+ kvm_skip_emulated_instruction(vcpu);
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
static int emulator_read_write_onepage(unsigned long addr, void *val,
unsigned int bytes,
struct x86_exception *exception,
@@ -5555,6 +5585,9 @@ 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;
@@ -6616,6 +6649,9 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
return EMULATE_DONE;
if (r == EMULATION_FAILED) {
+ if (vcpu->run->exit_reason == KVM_EXIT_SPP)
+ return EMULATE_USER_EXIT;
+
if (reexecute_instruction(vcpu, cr2, write_fault_to_spt,
emulation_type))
return EMULATE_DONE;
--
2.17.2
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