[PATCH v2 8/9] KVM: x86: add force_intercept_exceptions_mask

[Maxim Levitsky]

This parameter will be used by VMX and SVM code to force
interception of a set of exceptions, given by a bitmask
for guest debug and/or kvm debug.

This option is not intended for production.

This is based on an idea first shown here:
https://patchwork.kernel.org/project/kvm/patch/20160301192822.GD22677@pd.tnic/

CC: Borislav Petkov <bp at suse.de>
Signed-off-by: Maxim Levitsky <mlevitsk at redhat.com>
---
 arch/x86/kvm/x86.c | 3 +++
 arch/x86/kvm/x86.h | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3627ce8fe5bb..1a51031d64d8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -176,6 +176,9 @@ module_param(force_emulation_prefix, bool, S_IRUGO);
 int __read_mostly pi_inject_timer = -1;
 module_param(pi_inject_timer, bint, S_IRUGO | S_IWUSR);
 
+uint force_intercept_exceptions_mask;
+module_param(force_intercept_exceptions_mask, uint, S_IRUGO | S_IWUSR);
+EXPORT_SYMBOL_GPL(force_intercept_exceptions_mask);
 /*
  * Restoring the host value for MSRs that are only consumed when running in
  * usermode, e.g. SYSCALL MSRs and TSC_AUX, can be deferred until the CPU
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index daccf20fbcd5..644480711ff7 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -311,6 +311,8 @@ extern struct static_key kvm_no_apic_vcpu;
 
 extern bool report_ignored_msrs;
 
+extern uint force_intercept_exceptions_mask;
+
 static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
 {
 	return pvclock_scale_delta(nsec, vcpu->arch.virtual_tsc_mult,
-- 
2.26.2