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From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Joerg Roedel <joro@8bytes.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org, Jim Mattson <jmattson@google.com>,
	x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH v6 2/4] KVM: x86: report negative values from wrmsr emulation to userspace
Date: Wed, 23 Sep 2020 00:10:23 +0300	[thread overview]
Message-ID: <20200922211025.175547-3-mlevitsk@redhat.com> (raw)
In-Reply-To: <20200922211025.175547-1-mlevitsk@redhat.com>

This will allow the KVM to report such errors (e.g -ENOMEM)
to the userspace.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/emulate.c | 7 +++++--
 arch/x86/kvm/x86.c     | 6 +++++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 1d450d7710d63..d855304f5a509 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3702,13 +3702,16 @@ static int em_dr_write(struct x86_emulate_ctxt *ctxt)
 static int em_wrmsr(struct x86_emulate_ctxt *ctxt)
 {
 	u64 msr_data;
+	int ret;
 
 	msr_data = (u32)reg_read(ctxt, VCPU_REGS_RAX)
 		| ((u64)reg_read(ctxt, VCPU_REGS_RDX) << 32);
-	if (ctxt->ops->set_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), msr_data))
+
+	ret = ctxt->ops->set_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), msr_data);
+	if (ret > 0)
 		return emulate_gp(ctxt, 0);
 
-	return X86EMUL_CONTINUE;
+	return ret < 0 ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE;
 }
 
 static int em_rdmsr(struct x86_emulate_ctxt *ctxt)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 063d70e736f7f..e4b07be450d4e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1612,8 +1612,12 @@ int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu)
 {
 	u32 ecx = kvm_rcx_read(vcpu);
 	u64 data = kvm_read_edx_eax(vcpu);
+	int ret = kvm_set_msr(vcpu, ecx, data);
 
-	if (kvm_set_msr(vcpu, ecx, data)) {
+	if (ret < 0)
+		return ret;
+
+	if (ret > 0) {
 		trace_kvm_msr_write_ex(ecx, data);
 		kvm_inject_gp(vcpu, 0);
 		return 1;
-- 
2.26.2


  parent reply	other threads:[~2020-09-22 21:10 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-22 21:10 [PATCH v6 0/4] KVM: nSVM: ondemand nested state allocation Maxim Levitsky
2020-09-22 21:10 ` [PATCH v6 1/4] KVM: x86: xen_hvm_config: cleanup return values Maxim Levitsky
2020-09-22 21:10 ` Maxim Levitsky [this message]
2020-10-26 19:40   ` [PATCH v6 2/4] KVM: x86: report negative values from wrmsr emulation to userspace Qian Cai
2020-10-27 20:31     ` Qian Cai
2020-10-28  8:51       ` Maxim Levitsky
2020-09-22 21:10 ` [PATCH v6 3/4] KVM: x86: allow kvm_x86_ops.set_efer to return an error value Maxim Levitsky
2020-09-29  5:12   ` Sean Christopherson
2020-09-22 21:10 ` [PATCH v6 4/4] KVM: nSVM: implement on demand allocation of the nested state Maxim Levitsky
2020-09-29  5:15   ` Sean Christopherson
2020-09-30 15:35     ` Maxim Levitsky
2020-10-01  0:26       ` Sean Christopherson
2020-09-30 15:36 ` [PATCH v6 0/4] KVM: nSVM: ondemand nested state allocation Maxim Levitsky

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