[PATCH v3 2/6] KVM: x86: add force_intercept_exceptions_mask

Maxim Levitsky
2021-08-11T12:30:17Z

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

CC: Borislav Petkov <bp@suse.de>
Signed-off-by: Maxim Levitsky <mlevitsk@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 fdc0c18339fb..092e2fad3c0d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -184,6 +184,9 @@ 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 7d66d63dc55a..2b59825213c7 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -347,6 +347,8 @@ 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,
--
2.26.3