[PATCH v12 04/77] KVM: x86: add kvm_arch_vcpu_set_regs()

Adalbert Lazăr
2021-10-06T17:30:00Z

From: Nicu?or C??u <nicu.citu at icloud.com>

This is needed for the KVMI_VCPU_SET_REGISTERS command, which allows
an introspection tool to override the kvm_regs structure for a specific
vCPU without clearing the pending exception.

Signed-off-by: Nicu?or C??u <nicu.citu at icloud.com>
Signed-off-by: Adalbert Laz?r <alazar at bitdefender.com>
---
 arch/x86/kvm/x86.c       | 13 ++++++++++---
 include/linux/kvm_host.h |  2 ++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f7d09757b85f..bbcd256dc2f4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10104,8 +10104,15 @@ static void __set_regs(struct kvm_vcpu *vcpu, struct
kvm_regs *regs)

 	kvm_rip_write(vcpu, regs->rip);
 	kvm_set_rflags(vcpu, regs->rflags | X86_EFLAGS_FIXED);
+}
+
+void kvm_arch_vcpu_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs,
+			    bool clear_exception)
+{
+	__set_regs(vcpu, regs);

-	vcpu->arch.exception.pending = false;
+	if (clear_exception)
+		vcpu->arch.exception.pending = false;

 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 }
@@ -10113,7 +10120,7 @@ static void __set_regs(struct kvm_vcpu *vcpu, struct
kvm_regs *regs)
 int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
 {
 	vcpu_load(vcpu);
-	__set_regs(vcpu, regs);
+	kvm_arch_vcpu_set_regs(vcpu, regs, true);
 	vcpu_put(vcpu);
 	return 0;
 }
@@ -10601,7 +10608,7 @@ static void store_regs(struct kvm_vcpu *vcpu)
 static int sync_regs(struct kvm_vcpu *vcpu)
 {
 	if (vcpu->run->kvm_dirty_regs & KVM_SYNC_X86_REGS) {
-		__set_regs(vcpu, &vcpu->run->s.regs.regs);
+		kvm_arch_vcpu_set_regs(vcpu, &vcpu->run->s.regs.regs, true);
 		vcpu->run->kvm_dirty_regs &= ~KVM_SYNC_X86_REGS;
 	}
 	if (vcpu->run->kvm_dirty_regs & KVM_SYNC_X86_SREGS) {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7bc45e1879db..712642be3307 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1028,6 +1028,8 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
 int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
 void kvm_arch_vcpu_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
 int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
+void kvm_arch_vcpu_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs,
+			    bool clear_exception);
 int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
 				  struct kvm_sregs *sregs);
 void kvm_arch_vcpu_get_sregs(struct kvm_vcpu *vcpu,