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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] x86/vm_event: introduce vm_event_is_enabled()
commit 0ea539000c1d2fa93318c715e8f24c829f79f055
Author: Penny Zheng <Penny.Zheng@xxxxxxx>
AuthorDate: Thu Jan 15 17:28:37 2026 +0800
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jan 19 09:15:35 2026 +0100
x86/vm_event: introduce vm_event_is_enabled()
Function vm_event_is_enabled() is introduced to check if vm event is
enabled,
and also make the checking conditional upon CONFIG_VM_EVENT, which could
help
DCE a lot unreachable calls/codes, such as hvm_monitor_io(), etc,
when having VM_EVENT=n.
Signed-off-by: Penny Zheng <Penny.Zheng@xxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Jason Andryuk <jason.andryuk@xxxxxxx>
Acked-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
---
xen/arch/x86/hvm/emulate.c | 9 +++---
xen/arch/x86/hvm/hvm.c | 23 ++++++++++----
xen/arch/x86/hvm/svm/intr.c | 2 +-
xen/arch/x86/hvm/svm/svm.c | 46 +++++++++++++++------------
xen/arch/x86/hvm/vmx/intr.c | 2 +-
xen/arch/x86/hvm/vmx/vmx.c | 63 ++++++++++++++++++++++---------------
xen/arch/x86/include/asm/vm_event.h | 5 +++
xen/arch/x86/mm/mem_sharing.c | 3 ++
8 files changed, 96 insertions(+), 57 deletions(-)
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 2af4f30359..fe75b0516d 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -105,7 +105,7 @@ static int set_context_data(void *buffer, unsigned int size)
{
struct vcpu *curr = current;
- if ( curr->arch.vm_event )
+ if ( vm_event_is_enabled(curr) )
{
unsigned int safe_size =
min(size, curr->arch.vm_event->emul.read.size);
@@ -771,7 +771,7 @@ static void *hvmemul_map_linear_addr(
ASSERT(p2mt == p2m_ram_logdirty || !p2m_is_readonly(p2mt));
}
- if ( unlikely(curr->arch.vm_event) &&
+ if ( unlikely(vm_event_is_enabled(curr)) &&
curr->arch.vm_event->send_event &&
hvm_monitor_check_p2m(addr, gfn, pfec, npfec_kind_with_gla) )
{
@@ -1863,16 +1863,17 @@ static int hvmemul_rep_outs_set_context(
unsigned int bytes_per_rep,
unsigned long *reps)
{
- const struct arch_vm_event *ev = current->arch.vm_event;
+ const struct arch_vm_event *ev;
const uint8_t *ptr;
unsigned int avail;
unsigned long done;
int rc = X86EMUL_OKAY;
ASSERT(bytes_per_rep <= 4);
- if ( !ev )
+ if ( !vm_event_is_enabled(current) )
return X86EMUL_UNHANDLEABLE;
+ ev = current->arch.vm_event;
ptr = ev->emul.read.data;
avail = ev->emul.read.size;
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 0eafa515bb..07e54890d9 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -532,7 +532,7 @@ void hvm_do_resume(struct vcpu *v)
if ( !vcpu_ioreq_handle_completion(v) )
return;
- if ( unlikely(v->arch.vm_event) )
+ if ( unlikely(vm_event_is_enabled(v)) )
hvm_vm_event_do_resume(v);
/* Inject pending hw/sw event */
@@ -546,7 +546,8 @@ void hvm_do_resume(struct vcpu *v)
v->arch.hvm.inject_event.vector = HVM_EVENT_VECTOR_UNSET;
}
- if ( unlikely(v->arch.vm_event) && v->arch.monitor.next_interrupt_enabled )
+ if ( unlikely(vm_event_is_enabled(v)) &&
+ v->arch.monitor.next_interrupt_enabled )
{
struct x86_event info;
@@ -2095,7 +2096,7 @@ int hvm_handle_xsetbv(u32 index, u64 new_bv)
{
int rc;
- if ( index == 0 )
+ if ( index == 0 && vm_event_is_enabled(current) )
hvm_monitor_crX(XCR0, new_bv, current->arch.xcr0);
rc = x86emul_write_xcr(index, new_bv, NULL);
@@ -2266,6 +2267,8 @@ int hvm_set_cr0(unsigned long value, bool may_defer)
HVM_DBG_LOG(DBG_LEVEL_VMMU, "Update CR0 value = %lx", value);
+ may_defer &= vm_event_is_enabled(v);
+
if ( (u32)value != value )
{
HVM_DBG_LOG(DBG_LEVEL_1,
@@ -2401,6 +2404,8 @@ int hvm_set_cr3(unsigned long value, bool noflush, bool
may_defer)
struct vcpu *curr = current;
struct domain *currd = curr->domain;
+ may_defer &= vm_event_is_enabled(curr);
+
if ( value >> currd->arch.cpuid->extd.maxphysaddr )
{
HVM_DBG_LOG(DBG_LEVEL_1,
@@ -2456,6 +2461,8 @@ int hvm_set_cr4(unsigned long value, bool may_defer)
struct vcpu *v = current;
unsigned long old_cr, valid = hvm_cr4_guest_valid_bits(v->domain);
+ may_defer &= vm_event_is_enabled(v);
+
if ( value & ~valid )
{
HVM_DBG_LOG(DBG_LEVEL_1, "Bad CR4 %#lx (valid %#lx, rejected %#lx)",
@@ -3356,7 +3363,7 @@ static enum hvm_translation_result __hvm_copy(
return HVMTRANS_bad_gfn_to_mfn;
}
- if ( unlikely(v->arch.vm_event) &&
+ if ( unlikely(vm_event_is_enabled(v)) &&
(flags & HVMCOPY_linear) &&
v->arch.vm_event->send_event &&
hvm_monitor_check_p2m(addr, gfn, pfec, npfec_kind_with_gla) )
@@ -3503,7 +3510,9 @@ int hvm_vmexit_cpuid(struct cpu_user_regs *regs, unsigned
int inst_len)
regs->rcx = res.c;
regs->rdx = res.d;
- return hvm_monitor_cpuid(inst_len, leaf, subleaf);
+ return vm_event_is_enabled(curr)
+ ? hvm_monitor_cpuid(inst_len, leaf, subleaf)
+ : 0;
}
void hvm_rdtsc_intercept(struct cpu_user_regs *regs)
@@ -3635,6 +3644,7 @@ int hvm_msr_write_intercept(unsigned int msr, uint64_t
msr_content,
TRACE(TRC_HVM_MSR_WRITE, msr, msr_content, msr_content >> 32);
+ may_defer &= vm_event_is_enabled(v);
if ( may_defer && unlikely(monitored_msr(v->domain, msr)) )
{
uint64_t msr_old_content;
@@ -3803,7 +3813,8 @@ int hvm_descriptor_access_intercept(uint64_t exit_info,
struct vcpu *curr = current;
struct domain *currd = curr->domain;
- if ( currd->arch.monitor.descriptor_access_enabled )
+ if ( vm_event_is_enabled(curr) &&
+ currd->arch.monitor.descriptor_access_enabled )
{
ASSERT(curr->arch.vm_event);
hvm_monitor_descriptor_access(exit_info, vmx_exit_qualification,
diff --git a/xen/arch/x86/hvm/svm/intr.c b/xen/arch/x86/hvm/svm/intr.c
index 702c071e89..6453a46b85 100644
--- a/xen/arch/x86/hvm/svm/intr.c
+++ b/xen/arch/x86/hvm/svm/intr.c
@@ -130,7 +130,7 @@ void asmlinkage svm_intr_assist(void)
enum hvm_intblk intblk;
/* Block event injection while handling a sync vm_event. */
- if ( unlikely(v->arch.vm_event) && v->arch.vm_event->sync_event )
+ if ( unlikely(vm_event_is_enabled(v)) && v->arch.vm_event->sync_event )
return;
/* Crank the handle on interrupt state. */
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 564337bb4e..21f355a657 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -35,6 +35,7 @@
#include <asm/p2m.h>
#include <asm/paging.h>
#include <asm/processor.h>
+#include <asm/vm_event.h>
#include <asm/x86_emulate.h>
#include <public/sched.h>
@@ -2702,7 +2703,7 @@ void asmlinkage svm_vmexit_handler(void)
if ( !v->domain->debugger_attached )
{
unsigned int trap_type;
- int rc;
+ int rc = 0;
if ( likely(exit_reason != VMEXIT_ICEBP) )
{
@@ -2718,11 +2719,14 @@ void asmlinkage svm_vmexit_handler(void)
break;
}
- rc = hvm_monitor_debug(regs->rip,
- HVM_MONITOR_DEBUG_EXCEPTION,
- trap_type, insn_len, 0);
- if ( rc < 0 )
- goto unexpected_exit_type;
+ if ( vm_event_is_enabled(v) )
+ {
+ rc = hvm_monitor_debug(regs->rip,
+ HVM_MONITOR_DEBUG_EXCEPTION,
+ trap_type, insn_len, 0);
+ if ( rc < 0 )
+ goto unexpected_exit_type;
+ }
if ( !rc )
hvm_inject_exception(X86_EXC_DB,
trap_type, insn_len, X86_EVENT_NO_EC);
@@ -2746,9 +2750,10 @@ void asmlinkage svm_vmexit_handler(void)
}
else
{
- int rc = hvm_monitor_debug(regs->rip,
- HVM_MONITOR_SOFTWARE_BREAKPOINT,
- X86_ET_SW_EXC, insn_len, 0);
+ int rc = vm_event_is_enabled(v) ?
+ hvm_monitor_debug(regs->rip,
+ HVM_MONITOR_SOFTWARE_BREAKPOINT,
+ X86_ET_SW_EXC, insn_len, 0) : 0;
if ( rc < 0 )
goto unexpected_exit_type;
if ( !rc )
@@ -2899,17 +2904,19 @@ void asmlinkage svm_vmexit_handler(void)
break;
case VMEXIT_IOIO:
- {
- int rc;
+ if ( vm_event_is_enabled(v) )
+ {
+ int rc;
- rc = hvm_monitor_io(vmcb->ei.io.port,
- vmcb->ei.io.bytes,
- vmcb->ei.io.in,
- vmcb->ei.io.str);
- if ( rc < 0 )
- goto unexpected_exit_type;
- if ( rc )
- break;
+ rc = hvm_monitor_io(vmcb->ei.io.port,
+ vmcb->ei.io.bytes,
+ vmcb->ei.io.in,
+ vmcb->ei.io.str);
+ if ( rc < 0 )
+ goto unexpected_exit_type;
+ if ( rc )
+ break;
+ }
if ( !vmcb->ei.io.str )
{
@@ -2921,7 +2928,6 @@ void asmlinkage svm_vmexit_handler(void)
else if ( !hvm_emulate_one_insn(x86_insn_is_portio, "port I/O") )
hvm_inject_hw_exception(X86_EXC_GP, 0);
break;
- }
case VMEXIT_CR0_READ ... VMEXIT_CR15_READ:
case VMEXIT_CR0_WRITE ... VMEXIT_CR15_WRITE:
diff --git a/xen/arch/x86/hvm/vmx/intr.c b/xen/arch/x86/hvm/vmx/intr.c
index b35dc8c586..a8ced95871 100644
--- a/xen/arch/x86/hvm/vmx/intr.c
+++ b/xen/arch/x86/hvm/vmx/intr.c
@@ -239,7 +239,7 @@ void asmlinkage vmx_intr_assist(void)
}
/* Block event injection while handling a sync vm_event. */
- if ( unlikely(v->arch.vm_event) && v->arch.vm_event->sync_event )
+ if ( unlikely(vm_event_is_enabled(v)) && v->arch.vm_event->sync_event )
return;
#ifdef CONFIG_MEM_SHARING
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 524bce8307..89f9d9c7f6 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -47,6 +47,7 @@
#include <asm/shadow.h>
#include <asm/spec_ctrl.h>
#include <asm/stubs.h>
+#include <asm/vm_event.h>
#include <asm/x86_emulate.h>
#include <public/arch-x86/cpuid.h>
@@ -3335,7 +3336,8 @@ static int vmx_cr_access(cr_access_qual_t qual)
* VM_EVENT_FLAG_DENY-capable application, so the hvm_monitor_crX()
* return value is ignored for now.
*/
- hvm_monitor_crX(CR0, value, old);
+ if ( vm_event_is_enabled(curr) )
+ hvm_monitor_crX(CR0, value, old);
curr->arch.hvm.guest_cr[0] = value;
vmx_update_guest_cr(curr, 0, 0);
TRACE(TRC_HVM_CLTS);
@@ -4322,7 +4324,8 @@ void asmlinkage vmx_vmexit_handler(struct cpu_user_regs
*regs)
p2m_set_altp2m(v, idx);
}
- if ( unlikely(currd->arch.monitor.vmexit_enabled) )
+ if ( vm_event_is_enabled(v) &&
+ unlikely(currd->arch.monitor.vmexit_enabled) )
{
int rc;
@@ -4470,19 +4473,21 @@ void asmlinkage vmx_vmexit_handler(struct cpu_user_regs
*regs)
if ( !v->domain->debugger_attached )
{
unsigned long insn_len = 0;
- int rc;
+ int rc = 0;
unsigned long trap_type = MASK_EXTR(intr_info,
INTR_INFO_INTR_TYPE_MASK);
if ( trap_type >= X86_ET_SW_INT )
__vmread(VM_EXIT_INSTRUCTION_LEN, &insn_len);
- rc = hvm_monitor_debug(regs->rip,
- HVM_MONITOR_DEBUG_EXCEPTION,
- trap_type, insn_len, 0);
-
- if ( rc < 0 )
- goto exit_and_crash;
+ if ( vm_event_is_enabled(v) )
+ {
+ rc = hvm_monitor_debug(regs->rip,
+ HVM_MONITOR_DEBUG_EXCEPTION,
+ trap_type, insn_len, 0);
+ if ( rc < 0 )
+ goto exit_and_crash;
+ }
if ( !rc )
vmx_propagate_intr(intr_info);
}
@@ -4494,16 +4499,19 @@ void asmlinkage vmx_vmexit_handler(struct cpu_user_regs
*regs)
if ( !v->domain->debugger_attached )
{
unsigned long insn_len;
- int rc;
+ int rc = 0;
__vmread(VM_EXIT_INSTRUCTION_LEN, &insn_len);
- rc = hvm_monitor_debug(regs->rip,
- HVM_MONITOR_SOFTWARE_BREAKPOINT,
- X86_ET_SW_EXC,
- insn_len, 0);
+ if ( vm_event_is_enabled(v) )
+ {
+ rc = hvm_monitor_debug(regs->rip,
+ HVM_MONITOR_SOFTWARE_BREAKPOINT,
+ X86_ET_SW_EXC,
+ insn_len, 0);
- if ( rc < 0 )
- goto exit_and_crash;
+ if ( rc < 0 )
+ goto exit_and_crash;
+ }
if ( !rc )
vmx_propagate_intr(intr_info);
}
@@ -4758,16 +4766,20 @@ void asmlinkage vmx_vmexit_handler(struct cpu_user_regs
*regs)
};
} io_qual;
unsigned int bytes;
- int rc;
__vmread(EXIT_QUALIFICATION, &io_qual.raw);
bytes = io_qual.size + 1;
- rc = hvm_monitor_io(io_qual.port, bytes, io_qual.in, io_qual.str);
- if ( rc < 0 )
- goto exit_and_crash;
- if ( rc )
- break;
+ if ( vm_event_is_enabled(v) )
+ {
+ int rc;
+
+ rc = hvm_monitor_io(io_qual.port, bytes, io_qual.in, io_qual.str);
+ if ( rc < 0 )
+ goto exit_and_crash;
+ if ( rc )
+ break;
+ }
if ( io_qual.str )
{
@@ -4821,9 +4833,10 @@ void asmlinkage vmx_vmexit_handler(struct cpu_user_regs
*regs)
vmx_update_cpu_exec_control(v);
if ( v->arch.hvm.single_step )
{
- hvm_monitor_debug(regs->rip,
- HVM_MONITOR_SINGLESTEP_BREAKPOINT,
- 0, 0, 0);
+ if ( vm_event_is_enabled(v) )
+ hvm_monitor_debug(regs->rip,
+ HVM_MONITOR_SINGLESTEP_BREAKPOINT,
+ 0, 0, 0);
if ( v->domain->debugger_attached )
domain_pause_for_debugger();
diff --git a/xen/arch/x86/include/asm/vm_event.h
b/xen/arch/x86/include/asm/vm_event.h
index 46e77ed6d9..0310f30c18 100644
--- a/xen/arch/x86/include/asm/vm_event.h
+++ b/xen/arch/x86/include/asm/vm_event.h
@@ -45,4 +45,9 @@ void vm_event_sync_event(struct vcpu *v, bool value);
void vm_event_reset_vmtrace(struct vcpu *v);
+static inline bool vm_event_is_enabled(const struct vcpu *v)
+{
+ return IS_ENABLED(CONFIG_VM_EVENT) && v->arch.vm_event != NULL;
+}
+
#endif /* __ASM_X86_VM_EVENT_H__ */
diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index 4787b27964..b5a259af1d 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -648,6 +648,9 @@ int mem_sharing_notify_enomem(struct domain *d, unsigned
long gfn,
.u.mem_sharing.p2mt = p2m_ram_shared,
};
+ if ( !vm_event_is_enabled(current) )
+ return -EOPNOTSUPP;
+
if ( (rc = __vm_event_claim_slot(
d, d->vm_event_share, allow_sleep)) < 0 )
return rc;
--
generated by git-patchbot for /home/xen/git/xen.git#master
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