[PATCH 3/7] KVM: X86: Introduce more exit_fastpath_completion enum values
From: Paolo Bonzini
Date: Wed May 06 2020 - 12:11:16 EST
From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Adds a fastpath_t typedef since enum lines are a bit long, and replace
EXIT_FASTPATH_SKIP_EMUL_INS with two new exit_fastpath_completion enum values.
- EXIT_FASTPATH_EXIT_HANDLED kvm will still go through it's full run loop,
but it would skip invoking the exit handler.
- EXIT_FASTPATH_REENTER_GUEST complete fastpath, guest can be re-entered
without invoking the exit handler or going
back to vcpu_run
Tested-by: Haiwei Li <lihaiwei@xxxxxxxxxxx>
Cc: Haiwei Li <lihaiwei@xxxxxxxxxxx>
Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Message-Id: <1588055009-12677-4-git-send-email-wanpengli@xxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 4 +++-
arch/x86/kvm/svm/svm.c | 15 +++++++--------
arch/x86/kvm/vmx/vmx.c | 26 ++++++++++++++++++--------
arch/x86/kvm/x86.c | 19 ++++++++++---------
arch/x86/kvm/x86.h | 2 +-
5 files changed, 39 insertions(+), 27 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index cf6b0aff86c3..35a915787559 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -182,8 +182,10 @@ enum {
enum exit_fastpath_completion {
EXIT_FASTPATH_NONE,
- EXIT_FASTPATH_SKIP_EMUL_INS,
+ EXIT_FASTPATH_REENTER_GUEST,
+ EXIT_FASTPATH_EXIT_HANDLED,
};
+typedef enum exit_fastpath_completion fastpath_t;
struct x86_emulate_ctxt;
struct x86_exception;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index beab68dcbb7c..56c04d85ab60 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2890,8 +2890,7 @@ static void svm_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2)
*info2 = control->exit_info_2;
}
-static int handle_exit(struct kvm_vcpu *vcpu,
- enum exit_fastpath_completion exit_fastpath)
+static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
{
struct vcpu_svm *svm = to_svm(vcpu);
struct kvm_run *kvm_run = vcpu->run;
@@ -2949,10 +2948,10 @@ static int handle_exit(struct kvm_vcpu *vcpu,
__func__, svm->vmcb->control.exit_int_info,
exit_code);
- if (exit_fastpath == EXIT_FASTPATH_SKIP_EMUL_INS) {
- kvm_skip_emulated_instruction(vcpu);
+ if (exit_fastpath != EXIT_FASTPATH_NONE)
return 1;
- } else if (exit_code >= ARRAY_SIZE(svm_exit_handlers)
+
+ if (exit_code >= ARRAY_SIZE(svm_exit_handlers)
|| !svm_exit_handlers[exit_code]) {
vcpu_unimpl(vcpu, "svm: unexpected exit reason 0x%x\n", exit_code);
dump_vmcb(vcpu);
@@ -3321,7 +3320,7 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)
svm_complete_interrupts(svm);
}
-static enum exit_fastpath_completion svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
+static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
{
if (!is_guest_mode(vcpu) &&
to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
@@ -3333,9 +3332,9 @@ static enum exit_fastpath_completion svm_exit_handlers_fastpath(struct kvm_vcpu
void __svm_vcpu_run(unsigned long vmcb_pa, unsigned long *regs);
-static enum exit_fastpath_completion svm_vcpu_run(struct kvm_vcpu *vcpu)
+static fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
{
- enum exit_fastpath_completion exit_fastpath;
+ fastpath_t exit_fastpath;
struct vcpu_svm *svm = to_svm(vcpu);
svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX];
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ad57c4744b99..215ae9682da1 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5900,8 +5900,7 @@ void dump_vmcs(void)
* The guest has exited. See if we can fix it or if we need userspace
* assistance.
*/
-static int vmx_handle_exit(struct kvm_vcpu *vcpu,
- enum exit_fastpath_completion exit_fastpath)
+static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
u32 exit_reason = vmx->exit_reason;
@@ -6008,10 +6007,8 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
}
}
- if (exit_fastpath == EXIT_FASTPATH_SKIP_EMUL_INS) {
- kvm_skip_emulated_instruction(vcpu);
+ if (exit_fastpath != EXIT_FASTPATH_NONE)
return 1;
- }
if (exit_reason >= kvm_vmx_max_exit_handlers)
goto unexpected_vmexit;
@@ -6602,7 +6599,7 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp)
}
}
-static enum exit_fastpath_completion vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
+static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
{
switch (to_vmx(vcpu)->exit_reason) {
case EXIT_REASON_MSR_WRITE:
@@ -6614,12 +6611,13 @@ static enum exit_fastpath_completion vmx_exit_handlers_fastpath(struct kvm_vcpu
bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched);
-static enum exit_fastpath_completion vmx_vcpu_run(struct kvm_vcpu *vcpu)
+static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
{
- enum exit_fastpath_completion exit_fastpath;
+ fastpath_t exit_fastpath;
struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long cr3, cr4;
+reenter_guest:
/* Record the guest's net vcpu time for enforced NMI injections. */
if (unlikely(!enable_vnmi &&
vmx->loaded_vmcs->soft_vnmi_blocked))
@@ -6798,6 +6796,18 @@ static enum exit_fastpath_completion vmx_vcpu_run(struct kvm_vcpu *vcpu)
return EXIT_FASTPATH_NONE;
exit_fastpath = vmx_exit_handlers_fastpath(vcpu);
+ if (exit_fastpath == EXIT_FASTPATH_REENTER_GUEST) {
+ if (!kvm_vcpu_exit_request(vcpu)) {
+ /*
+ * FIXME: this goto should be a loop in vcpu_enter_guest,
+ * but it would incur the cost of a retpoline for now.
+ * Revisit once static calls are available.
+ */
+ goto reenter_guest;
+ }
+ exit_fastpath = EXIT_FASTPATH_EXIT_HANDLED;
+ }
+
return exit_fastpath;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 999275795bba..98e5b79063b7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1616,27 +1616,28 @@ static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data
return 1;
}
-enum exit_fastpath_completion handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
+fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu)
{
u32 msr = kvm_rcx_read(vcpu);
u64 data;
- int ret = 0;
+ fastpath_t ret = EXIT_FASTPATH_NONE;
switch (msr) {
case APIC_BASE_MSR + (APIC_ICR >> 4):
data = kvm_read_edx_eax(vcpu);
- ret = handle_fastpath_set_x2apic_icr_irqoff(vcpu, data);
+ if (!handle_fastpath_set_x2apic_icr_irqoff(vcpu, data)) {
+ kvm_skip_emulated_instruction(vcpu);
+ ret = EXIT_FASTPATH_EXIT_HANDLED;
+ }
break;
default:
- return EXIT_FASTPATH_NONE;
+ break;
}
- if (!ret) {
+ if (ret != EXIT_FASTPATH_NONE)
trace_kvm_msr_write(msr, data);
- return EXIT_FASTPATH_SKIP_EMUL_INS;
- }
- return EXIT_FASTPATH_NONE;
+ return ret;
}
EXPORT_SYMBOL_GPL(handle_fastpath_set_msr_irqoff);
@@ -8174,7 +8175,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
bool req_int_win =
dm_request_for_irq_injection(vcpu) &&
kvm_cpu_accept_dm_intr(vcpu);
- enum exit_fastpath_completion exit_fastpath;
+ fastpath_t exit_fastpath;
bool req_immediate_exit = false;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index e02fe28254b6..6eb62e97e59f 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -274,7 +274,7 @@ bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn,
bool kvm_vector_hashing_enabled(void);
int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
int emulation_type, void *insn, int insn_len);
-enum exit_fastpath_completion handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu);
+fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu);
extern u64 host_xcr0;
extern u64 supported_xcr0;
--
2.18.2