From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
Arnd Bergmann <arnd@arndb.de>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
Ajay Garg <ajaygargnsit@gmail.com>
Subject: [PATCH v3 7/8] KVM: x86: Reject fixeds-size Hyper-V hypercalls with non-zero "var_cnt"
Date: Tue, 7 Dec 2021 22:09:25 +0000 [thread overview]
Message-ID: <20211207220926.718794-8-seanjc@google.com> (raw)
In-Reply-To: <20211207220926.718794-1-seanjc@google.com>
Reject Hyper-V hypercalls if the guest specifies a non-zero variable size
header (var_cnt in KVM) for a hypercall that has a fixed header size.
Per the TLFS:
It is illegal to specify a non-zero variable header size for a
hypercall that is not explicitly documented as accepting variable sized
input headers. In such a case the hypercall will result in a return
code of HV_STATUS_INVALID_HYPERCALL_INPUT.
Note, at least some of the various DEBUG commands likely aren't allowed
to use variable size headers, but the TLFS documentation doesn't clearly
state what is/isn't allowed. Omit them for now to avoid unnecessary
breakage.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/hyperv.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index f33a5e890048..522ccd2f0db4 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2250,14 +2250,14 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
switch (hc.code) {
case HVCALL_NOTIFY_LONG_SPIN_WAIT:
- if (unlikely(hc.rep)) {
+ if (unlikely(hc.rep || hc.var_cnt)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
kvm_vcpu_on_spin(vcpu, true);
break;
case HVCALL_SIGNAL_EVENT:
- if (unlikely(hc.rep)) {
+ if (unlikely(hc.rep || hc.var_cnt)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
@@ -2267,7 +2267,7 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
fallthrough; /* maybe userspace knows this conn_id */
case HVCALL_POST_MESSAGE:
/* don't bother userspace if it has no way to handle it */
- if (unlikely(hc.rep || !to_hv_synic(vcpu)->active)) {
+ if (unlikely(hc.rep || hc.var_cnt || !to_hv_synic(vcpu)->active)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
@@ -2280,14 +2280,14 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
kvm_hv_hypercall_complete_userspace;
return 0;
case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
- if (unlikely(!hc.rep_cnt || hc.rep_idx)) {
+ if (unlikely(!hc.rep_cnt || hc.rep_idx || hc.var_cnt)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
ret = kvm_hv_flush_tlb(vcpu, &hc, false);
break;
case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
- if (unlikely(hc.rep)) {
+ if (unlikely(hc.rep || hc.var_cnt)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
@@ -2308,7 +2308,7 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
ret = kvm_hv_flush_tlb(vcpu, &hc, true);
break;
case HVCALL_SEND_IPI:
- if (unlikely(hc.rep)) {
+ if (unlikely(hc.rep || hc.var_cnt)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
--
2.34.1.400.ga245620fadb-goog
next prev parent reply other threads:[~2021-12-07 22:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-07 22:09 [PATCH v3 0/8] KVM: x86: Hyper-V hypercall fix and cleanups Sean Christopherson
2021-12-07 22:09 ` [PATCH v3 1/8] KVM: x86: Ignore sparse banks size for an "all CPUs", non-sparse IPI req Sean Christopherson
2021-12-09 11:19 ` Paolo Bonzini
2021-12-07 22:09 ` [PATCH v3 2/8] KVM: x86: Get the number of Hyper-V sparse banks from the VARHEAD field Sean Christopherson
2021-12-07 22:09 ` [PATCH v3 3/8] KVM: x86: Refactor kvm_hv_flush_tlb() to reduce indentation Sean Christopherson
2021-12-07 22:09 ` [PATCH v3 4/8] KVM: x86: Add a helper to get the sparse VP_SET for IPIs and TLB flushes Sean Christopherson
2021-12-07 22:09 ` [PATCH v3 5/8] KVM: x86: Don't bother reading sparse banks that end up being ignored Sean Christopherson
2021-12-07 22:09 ` [PATCH v3 6/8] KVM: x86: Shove vp_bitmap handling down into sparse_set_to_vcpu_mask() Sean Christopherson
2021-12-07 22:09 ` Sean Christopherson [this message]
2021-12-09 9:55 ` [PATCH v3 7/8] KVM: x86: Reject fixeds-size Hyper-V hypercalls with non-zero "var_cnt" Vitaly Kuznetsov
2021-12-07 22:09 ` [PATCH v3 8/8] KVM: x86: Add checks for reserved-to-zero Hyper-V hypercall fields Sean Christopherson
2022-02-01 13:47 ` [PATCH v3 0/8] KVM: x86: Hyper-V hypercall fix and cleanups Paolo Bonzini
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