From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: oupton@google.com
Subject: [FYI PATCH 3/3] KVM: nVMX: Check IO instruction VM-exit conditions
Date: Mon, 24 Feb 2020 19:56:36 +0100 [thread overview]
Message-ID: <1582570596-45387-4-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1582570596-45387-1-git-send-email-pbonzini@redhat.com>
From: Oliver Upton <oupton@google.com>
Consult the 'unconditional IO exiting' and 'use IO bitmaps' VM-execution
controls when checking instruction interception. If the 'use IO bitmaps'
VM-execution control is 1, check the instruction access against the IO
bitmaps to determine if the instruction causes a VM-exit.
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/vmx/nested.c | 2 +-
arch/x86/kvm/vmx/vmx.c | 57 ++++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 52 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index f979832c394d..e920d7834d73 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5353,7 +5353,7 @@ static bool nested_vmx_exit_handled_io(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
unsigned long exit_qualification;
- unsigned int port;
+ unsigned short port;
int size;
if (!nested_cpu_has(vmcs12, CPU_BASED_USE_IO_BITMAPS))
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5801a86f9c24..63aaf44edd1f 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7145,6 +7145,39 @@ static void vmx_request_immediate_exit(struct kvm_vcpu *vcpu)
to_vmx(vcpu)->req_immediate_exit = true;
}
+static int vmx_check_intercept_io(struct kvm_vcpu *vcpu,
+ struct x86_instruction_info *info)
+{
+ struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
+ unsigned short port;
+ bool intercept;
+ int size;
+
+ if (info->intercept == x86_intercept_in ||
+ info->intercept == x86_intercept_ins) {
+ port = info->src_val;
+ size = info->dst_bytes;
+ } else {
+ port = info->dst_val;
+ size = info->src_bytes;
+ }
+
+ /*
+ * If the 'use IO bitmaps' VM-execution control is 0, IO instruction
+ * VM-exits depend on the 'unconditional IO exiting' VM-execution
+ * control.
+ *
+ * Otherwise, IO instruction VM-exits are controlled by the IO bitmaps.
+ */
+ if (!nested_cpu_has(vmcs12, CPU_BASED_USE_IO_BITMAPS))
+ intercept = nested_cpu_has(vmcs12,
+ CPU_BASED_UNCOND_IO_EXITING);
+ else
+ intercept = nested_vmx_check_io_bitmaps(vcpu, port, size);
+
+ return intercept ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE;
+}
+
static int vmx_check_intercept(struct kvm_vcpu *vcpu,
struct x86_instruction_info *info,
enum x86_intercept_stage stage)
@@ -7152,18 +7185,30 @@ static int vmx_check_intercept(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
+ switch (info->intercept) {
/*
* RDPID causes #UD if disabled through secondary execution controls.
* Because it is marked as EmulateOnUD, we need to intercept it here.
*/
- if (info->intercept == x86_intercept_rdtscp &&
- !nested_cpu_has2(vmcs12, SECONDARY_EXEC_RDTSCP)) {
- ctxt->exception.vector = UD_VECTOR;
- ctxt->exception.error_code_valid = false;
- return X86EMUL_PROPAGATE_FAULT;
- }
+ case x86_intercept_rdtscp:
+ if (!nested_cpu_has2(vmcs12, SECONDARY_EXEC_RDTSCP)) {
+ ctxt->exception.vector = UD_VECTOR;
+ ctxt->exception.error_code_valid = false;
+ return X86EMUL_PROPAGATE_FAULT;
+ }
+ break;
+
+ case x86_intercept_in:
+ case x86_intercept_ins:
+ case x86_intercept_out:
+ case x86_intercept_outs:
+ return vmx_check_intercept_io(vcpu, info);
/* TODO: check more intercepts... */
+ default:
+ break;
+ }
+
return X86EMUL_UNHANDLEABLE;
}
--
1.8.3.1
prev parent reply other threads:[~2020-02-24 18:56 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-24 18:56 [FYI PATCH 0/3] CVE-2020-2732 Paolo Bonzini
2020-02-24 18:56 ` [FYI PATCH 1/3] KVM: nVMX: Don't emulate instructions in guest mode Paolo Bonzini
2020-02-29 18:00 ` Jan Kiszka
2020-02-29 18:33 ` Oliver Upton
2020-02-29 19:00 ` Jim Mattson
2020-02-29 19:21 ` Jan Kiszka
2020-02-29 20:17 ` Jim Mattson
2020-02-29 20:36 ` Jan Kiszka
2020-02-24 18:56 ` [FYI PATCH 2/3] KVM: nVMX: Refactor IO bitmap checks into helper function Paolo Bonzini
2020-02-24 18:56 ` Paolo Bonzini [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1582570596-45387-4-git-send-email-pbonzini@redhat.com \
--to=pbonzini@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=oupton@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).