From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.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-kernel@vger.kernel.org,
Liran Alon <liran.alon@oracle.com>
Subject: [PATCH v2 14/14] KVM: x86: Add comments to document various emulation types
Date: Tue, 27 Aug 2019 14:40:40 -0700 [thread overview]
Message-ID: <20190827214040.18710-15-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190827214040.18710-1-sean.j.christopherson@intel.com>
Document the intended usage of each emulation type as each exists to
handle an edge case of one kind or another and can be easily
misinterpreted at first glance.
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/include/asm/kvm_host.h | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3f524cea20ad..8221e68bbb0c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1308,6 +1308,36 @@ extern u64 kvm_default_tsc_scaling_ratio;
extern u64 kvm_mce_cap_supported;
+/*
+ * EMULTYPE_NO_DECODE - Set when re-emulating an instruction (after completing
+ * userspace I/O) to indicate that the emulation context
+ * should be resued as is, i.e. skip initialization of
+ * emulation context, instruction fetch and decode.
+ *
+ * EMULTYPE_TRAP_UD - Set when emulating an intercepted #UD from hardware.
+ * Indicates that only select instructions (tagged with
+ * EmulateOnUD) should be emulated (to minimize the emulator
+ * attack surface). See also EMULTYPE_TRAP_UD_FORCED.
+ *
+ * EMULTYPE_SKIP - Set when emulating solely to skip an instruction, i.e. to
+ * decode the instruction length. For use *only* by
+ * kvm_x86_ops->skip_emulated_instruction() implementations.
+ *
+ * EMULTYPE_ALLOW_RETRY - Set when the emulator should resume the guest to
+ * retry native execution under certain conditions.
+ *
+ * EMULTYPE_TRAP_UD_FORCED - Set when emulating an intercepted #UD that was
+ * triggered by KVM's magic "force emulation" prefix,
+ * which is opt in via module param (off by default).
+ * Bypasses EmulateOnUD restriction despite emulating
+ * due to an intercepted #UD (see EMULTYPE_TRAP_UD).
+ * Used to test the full emulator from userspace.
+ *
+ * EMULTYPE_VMWARE_GP - Set when emulating an intercepted #GP for VMware
+ * backdoor emulation, which is opt in via module param.
+ * VMware backoor emulation handles select instructions
+ * and reinjects the #GP for all other cases.
+ */
#define EMULTYPE_NO_DECODE (1 << 0)
#define EMULTYPE_TRAP_UD (1 << 1)
#define EMULTYPE_SKIP (1 << 2)
--
2.22.0
next prev parent reply other threads:[~2019-08-27 21:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 21:40 [PATCH v2 00/14] KVM: x86: Remove emulation_result enums Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 01/14] KVM: x86: Relocate MMIO exit stats counting Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 02/14] KVM: x86: Clean up handle_emulation_failure() Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 03/14] KVM: x86: Refactor kvm_vcpu_do_singlestep() to remove out param Sean Christopherson
2019-09-17 15:07 ` Paolo Bonzini
2019-08-27 21:40 ` [PATCH v2 04/14] KVM: x86: Don't attempt VMWare emulation on #GP with non-zero error code Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 05/14] KVM: x86: Move #GP injection for VMware into x86_emulate_instruction() Sean Christopherson
2019-08-27 22:03 ` Liran Alon
2019-08-27 21:40 ` [PATCH v2 06/14] KVM: x86: Add explicit flag for forced emulation on #UD Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 07/14] KVM: x86: Move #UD injection for failed emulation into emulation code Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 08/14] KVM: x86: Exit to userspace on emulation skip failure Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 09/14] KVM: x86: Handle emulation failure directly in kvm_task_switch() Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 10/14] KVM: x86: Move triple fault request into RM int injection Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 11/14] KVM: VMX: Remove EMULATE_FAIL handling in handle_invalid_guest_state() Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 12/14] KVM: x86: Remove emulation_result enums, EMULATE_{DONE,FAIL,USER_EXIT} Sean Christopherson
2019-08-27 21:40 ` [PATCH v2 13/14] KVM: VMX: Handle single-step #DB for EMULTYPE_SKIP on EPT misconfig Sean Christopherson
2019-08-27 21:40 ` Sean Christopherson [this message]
2019-09-17 15:14 ` [PATCH v2 00/14] KVM: x86: Remove emulation_result enums Paolo Bonzini
2019-10-25 11:00 ` Alexander Graf
2019-11-06 0:58 ` Sean Christopherson
2019-11-06 12:17 ` Paolo Bonzini
2019-11-06 22:27 ` Sean Christopherson
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=20190827214040.18710-15-sean.j.christopherson@intel.com \
--to=sean.j.christopherson@intel.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=liran.alon@oracle.com \
--cc=pbonzini@redhat.com \
--cc=rkrcmar@redhat.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.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).