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

From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	Ingo Molnar <mingo@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sean Christopherson <seanjc@google.com>,
	Marc Zyngier <maz@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-kernel@vger.kernel.org (open list),
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Stefano Garzarella <sgarzare@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Jonathan Corbet <corbet@lwn.net>, Jessica Yu <jeyu@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Jan Kiszka <jan.kiszka@siemens.com>,
	Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu (open list:KERNEL VIRTUAL MACHINE
	FOR ARM64 (KVM/arm64)), Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Vasily Gorbik <gor@linux.ibm.com>, Joerg Roedel <joro@8bytes.org>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Jim Mattson <jmattson@google.com>,
	Cornelia Huck <cohuck@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	linux-s390@vger.kernel.org (open list:S390),
	Heiko Carstens <hca@linux.ibm.com>,
	Kieran Bingham <kbingham@kernel.org>,
	linux-doc@vger.kernel.org (open list:DOCUMENTATION),
	linux-arm-kernel@lists.infradead.org (moderated list:KERNEL
	VIRTUAL MACHINE FOR ARM64 (KVM/arm64)),
	James Morse <james.morse@arm.com>, Borislav Petkov <bp@suse.de>
Subject: [PATCH v2 8/9] KVM: x86: add force_intercept_exceptions_mask
Date: Thu,  1 Apr 2021 16:54:50 +0300	[thread overview]
Message-ID: <20210401135451.1004564-9-mlevitsk@redhat.com> (raw)
In-Reply-To: <20210401135451.1004564-1-mlevitsk@redhat.com>

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@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 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


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