From: Hou Wenlong <houwenlong93@linux.alibaba.com>
To: kvm@vger.kernel.org
Cc: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/4] KVM: x86: Add an emulation type to handle completion of user exits
Date: Tue, 2 Nov 2021 17:15:30 +0800 [thread overview]
Message-ID: <8f8c8e268b65f31d55c2881a4b30670946ecfa0d.1635842679.git.houwenlong93@linux.alibaba.com> (raw)
In-Reply-To: <cover.1635842679.git.houwenlong93@linux.alibaba.com>
The next patch would use kvm_emulate_instruction() with
EMULTYPE_SKIP in complete_userspace_io callback to fix a
problem in msr access emulation. However, EMULTYPE_SKIP
only updates RIP, more things like updating interruptibility
state and injecting single-step #DBs would be done in the
callback. Since the emulator also does those things after
x86_emulate_insn(), add a new emulation type to pair with
EMULTYPE_SKIP to do those things for completion of user exits
within the emulator.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
---
arch/x86/include/asm/kvm_host.h | 8 +++++++-
arch/x86/kvm/x86.c | 13 ++++++++++---
2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 88fce6ab4bbd..b99e62b39097 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1635,7 +1635,8 @@ extern u64 kvm_mce_cap_supported;
*
* 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.
+ * kvm_x86_ops.skip_emulated_instruction() implementations if
+ * EMULTYPE_COMPLETE_USER_EXIT is not set.
*
* EMULTYPE_ALLOW_RETRY_PF - Set when the emulator should resume the guest to
* retry native execution under certain conditions,
@@ -1655,6 +1656,10 @@ extern u64 kvm_mce_cap_supported;
*
* EMULTYPE_PF - Set when emulating MMIO by way of an intercepted #PF, in which
* case the CR2/GPA value pass on the stack is valid.
+ *
+ * EMULTYPE_COMPLETE_USER_EXIT - Set when the emulator should update interruptibility
+ * state and inject single-step #DBs after skipping
+ * an instruction (after completing userspace I/O).
*/
#define EMULTYPE_NO_DECODE (1 << 0)
#define EMULTYPE_TRAP_UD (1 << 1)
@@ -1663,6 +1668,7 @@ extern u64 kvm_mce_cap_supported;
#define EMULTYPE_TRAP_UD_FORCED (1 << 4)
#define EMULTYPE_VMWARE_GP (1 << 5)
#define EMULTYPE_PF (1 << 6)
+#define EMULTYPE_COMPLETE_USER_EXIT (1 << 7)
int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type);
int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3d7fc5c21ceb..a961b49c8c44 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8119,9 +8119,10 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
}
/*
- * Note, EMULTYPE_SKIP is intended for use *only* by vendor callbacks
- * for kvm_skip_emulated_instruction(). The caller is responsible for
- * updating interruptibility state and injecting single-step #DBs.
+ * EMULTYPE_SKIP without EMULTYPE_COMPLETE_USER_EXIT is intended for
+ * use *only* by vendor callbacks for kvm_skip_emulated_instruction().
+ * The caller is responsible for updating interruptibility state and
+ * injecting single-step #DBs.
*/
if (emulation_type & EMULTYPE_SKIP) {
if (ctxt->mode != X86EMUL_MODE_PROT64)
@@ -8129,6 +8130,11 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
else
ctxt->eip = ctxt->_eip;
+ if (emulation_type & EMULTYPE_COMPLETE_USER_EXIT) {
+ r = 1;
+ goto writeback;
+ }
+
kvm_rip_write(vcpu, ctxt->eip);
if (ctxt->eflags & X86_EFLAGS_RF)
kvm_set_rflags(vcpu, ctxt->eflags & ~X86_EFLAGS_RF);
@@ -8198,6 +8204,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
else
r = 1;
+writeback:
if (writeback) {
unsigned long rflags = static_call(kvm_x86_get_rflags)(vcpu);
toggle_interruptibility(vcpu, ctxt->interruptibility);
--
2.31.1
next prev parent reply other threads:[~2021-11-02 9:15 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-22 2:59 [PATCH 0/2] KVM: some fixes about RDMSR/WRMSR instruction emulation Hou Wenlong
2021-10-22 2:59 ` [PATCH 1/2] KVM: VMX: fix instruction skipping when handling UD exception Hou Wenlong
2021-10-26 16:37 ` Sean Christopherson
2021-10-27 7:00 ` Hou Wenlong
2021-10-29 10:57 ` Hou Wenlong
2021-11-01 17:03 ` Sean Christopherson
2021-10-22 2:59 ` [PATCH 2/2] KVM: X86: Exit to userspace if RDMSR/WRMSR emulation returns X86EMUL_IO_NEEDED Hou Wenlong
2021-10-22 9:46 ` [PATCH 0/2] KVM: some fixes about RDMSR/WRMSR instruction emulation Paolo Bonzini
2021-10-22 15:10 ` Hou Wenlong
2021-11-02 9:15 ` [PATCH v2 0/4] KVM: x86: some fixes about msr access emulation Hou Wenlong
2021-11-02 9:15 ` [PATCH v2 1/4] KVM: x86: Handle 32-bit wrap of EIP for EMULTYPE_SKIP with flat code seg Hou Wenlong
2021-11-02 9:15 ` Hou Wenlong [this message]
2021-11-02 9:15 ` [PATCH v2 3/4] KVM: x86: Use different callback if msr access comes from the emulator Hou Wenlong
2021-11-26 17:39 ` Paolo Bonzini
2021-11-02 9:15 ` [PATCH v2 4/4] KVM: x86: Exit to userspace if RDMSR/WRMSR emulation returns X86EMUL_IO_NEEDED Hou Wenlong
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=8f8c8e268b65f31d55c2881a4b30670946ecfa0d.1635842679.git.houwenlong93@linux.alibaba.com \
--to=houwenlong93@linux.alibaba.com \
--cc=bp@alien8.de \
--cc=hpa@zytor.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=x86@kernel.org \
/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).