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x86/xen: Move Xen upcall handler

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Move the upcall handler to Xen-specific files.

No functional changes.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-2-brgerst@gmail.com
This commit is contained in:
Brian Gerst
2025-03-14 11:12:14 -04:00
committed by Ingo Molnar
parent 4476e7f814
commit 1ab7b5ed44
2 changed files with 69 additions and 72 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
arch/x86/entry/common.c
View File

@@ -21,11 +21,6 @@
#include <linux/uaccess.h>
#include <linux/init.h>
#ifdef CONFIG_XEN_PV
#include <xen/xen-ops.h>
#include <xen/events.h>
#endif
#include <asm/apic.h>
#include <asm/desc.h>
#include <asm/traps.h>
@@ -455,70 +450,3 @@ SYSCALL_DEFINE0(ni_syscall)
{
return -ENOSYS;
}
#ifdef CONFIG_XEN_PV
#ifndef CONFIG_PREEMPTION
/*
* Some hypercalls issued by the toolstack can take many 10s of
* seconds. Allow tasks running hypercalls via the privcmd driver to
* be voluntarily preempted even if full kernel preemption is
* disabled.
*
* Such preemptible hypercalls are bracketed by
* xen_preemptible_hcall_begin() and xen_preemptible_hcall_end()
* calls.
*/
DEFINE_PER_CPU(bool, xen_in_preemptible_hcall);
EXPORT_SYMBOL_GPL(xen_in_preemptible_hcall);
/*
* In case of scheduling the flag must be cleared and restored after
* returning from schedule as the task might move to a different CPU.
*/
static __always_inline bool get_and_clear_inhcall(void)
{
bool inhcall = __this_cpu_read(xen_in_preemptible_hcall);
__this_cpu_write(xen_in_preemptible_hcall, false);
return inhcall;
}
static __always_inline void restore_inhcall(bool inhcall)
{
__this_cpu_write(xen_in_preemptible_hcall, inhcall);
}
#else
static __always_inline bool get_and_clear_inhcall(void) { return false; }
static __always_inline void restore_inhcall(bool inhcall) { }
#endif
static void __xen_pv_evtchn_do_upcall(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
inc_irq_stat(irq_hv_callback_count);
xen_evtchn_do_upcall();
set_irq_regs(old_regs);
}
__visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
bool inhcall;
instrumentation_begin();
run_sysvec_on_irqstack_cond(__xen_pv_evtchn_do_upcall, regs);
inhcall = get_and_clear_inhcall();
if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) {
irqentry_exit_cond_resched();
instrumentation_end();
restore_inhcall(inhcall);
} else {
instrumentation_end();
irqentry_exit(regs, state);
}
}
#endif /* CONFIG_XEN_PV */

69
arch/x86/xen/enlighten_pv.c
View File

@@ -73,6 +73,7 @@
#include <asm/mwait.h>
#include <asm/pci_x86.h>
#include <asm/cpu.h>
#include <asm/irq_stack.h>
#ifdef CONFIG_X86_IOPL_IOPERM
#include <asm/io_bitmap.h>
#endif
@@ -94,6 +95,44 @@ void *xen_initial_gdt;
static int xen_cpu_up_prepare_pv(unsigned int cpu);
static int xen_cpu_dead_pv(unsigned int cpu);
#ifndef CONFIG_PREEMPTION
/*
* Some hypercalls issued by the toolstack can take many 10s of
* seconds. Allow tasks running hypercalls via the privcmd driver to
* be voluntarily preempted even if full kernel preemption is
* disabled.
*
* Such preemptible hypercalls are bracketed by
* xen_preemptible_hcall_begin() and xen_preemptible_hcall_end()
* calls.
*/
DEFINE_PER_CPU(bool, xen_in_preemptible_hcall);
EXPORT_SYMBOL_GPL(xen_in_preemptible_hcall);
/*
* In case of scheduling the flag must be cleared and restored after
* returning from schedule as the task might move to a different CPU.
*/
static __always_inline bool get_and_clear_inhcall(void)
{
bool inhcall = __this_cpu_read(xen_in_preemptible_hcall);
__this_cpu_write(xen_in_preemptible_hcall, false);
return inhcall;
}
static __always_inline void restore_inhcall(bool inhcall)
{
__this_cpu_write(xen_in_preemptible_hcall, inhcall);
}
#else
static __always_inline bool get_and_clear_inhcall(void) { return false; }
static __always_inline void restore_inhcall(bool inhcall) { }
#endif
struct tls_descs {
struct desc_struct desc[3];
};
@@ -687,6 +726,36 @@ DEFINE_IDTENTRY_RAW(xenpv_exc_machine_check)
}
#endif
static void __xen_pv_evtchn_do_upcall(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
inc_irq_stat(irq_hv_callback_count);
xen_evtchn_do_upcall();
set_irq_regs(old_regs);
}
__visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
bool inhcall;
instrumentation_begin();
run_sysvec_on_irqstack_cond(__xen_pv_evtchn_do_upcall, regs);
inhcall = get_and_clear_inhcall();
if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) {
irqentry_exit_cond_resched();
instrumentation_end();
restore_inhcall(inhcall);
} else {
instrumentation_end();
irqentry_exit(regs, state);
}
}
struct trap_array_entry {
void (*orig)(void);
void (*xen)(void);