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Diffstat (limited to 'arch/x86/xen/multicalls.c')
-rw-r--r--arch/x86/xen/multicalls.c159
1 files changed, 125 insertions, 34 deletions
diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
index ea54a08d8301..7237d56a9d3f 100644
--- a/arch/x86/xen/multicalls.c
+++ b/arch/x86/xen/multicalls.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* Xen hypercall batching.
*
@@ -22,26 +23,21 @@
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/debugfs.h>
+#include <linux/jump_label.h>
+#include <linux/printk.h>
#include <asm/xen/hypercall.h>
-#include "multicalls.h"
-#include "debugfs.h"
+#include "xen-ops.h"
#define MC_BATCH 32
-#define MC_DEBUG 0
-
#define MC_ARGS (MC_BATCH * 16)
struct mc_buffer {
unsigned mcidx, argidx, cbidx;
struct multicall_entry entries[MC_BATCH];
-#if MC_DEBUG
- struct multicall_entry debug[MC_BATCH];
- void *caller[MC_BATCH];
-#endif
unsigned char args[MC_ARGS];
struct callback {
void (*fn)(void *);
@@ -49,13 +45,105 @@ struct mc_buffer {
} callbacks[MC_BATCH];
};
+struct mc_debug_data {
+ struct multicall_entry entries[MC_BATCH];
+ void *caller[MC_BATCH];
+ size_t argsz[MC_BATCH];
+ unsigned long *args[MC_BATCH];
+};
+
static DEFINE_PER_CPU(struct mc_buffer, mc_buffer);
+static struct mc_debug_data mc_debug_data_early __initdata;
+static struct mc_debug_data __percpu *mc_debug_data_ptr;
DEFINE_PER_CPU(unsigned long, xen_mc_irq_flags);
+static struct static_key mc_debug __ro_after_init;
+static bool mc_debug_enabled __initdata;
+
+static struct mc_debug_data * __ref get_mc_debug(void)
+{
+ if (!mc_debug_data_ptr)
+ return &mc_debug_data_early;
+
+ return this_cpu_ptr(mc_debug_data_ptr);
+}
+
+static int __init xen_parse_mc_debug(char *arg)
+{
+ mc_debug_enabled = true;
+ static_key_slow_inc(&mc_debug);
+
+ return 0;
+}
+early_param("xen_mc_debug", xen_parse_mc_debug);
+
+static int __init mc_debug_enable(void)
+{
+ unsigned long flags;
+ struct mc_debug_data __percpu *mcdb;
+
+ if (!mc_debug_enabled)
+ return 0;
+
+ mcdb = alloc_percpu(struct mc_debug_data);
+ if (!mcdb) {
+ pr_err("xen_mc_debug inactive\n");
+ static_key_slow_dec(&mc_debug);
+ return -ENOMEM;
+ }
+
+ /* Be careful when switching to percpu debug data. */
+ local_irq_save(flags);
+ xen_mc_flush();
+ mc_debug_data_ptr = mcdb;
+ local_irq_restore(flags);
+
+ pr_info("xen_mc_debug active\n");
+
+ return 0;
+}
+early_initcall(mc_debug_enable);
+
+/* Number of parameters of hypercalls used via multicalls. */
+static const uint8_t hpcpars[] = {
+ [__HYPERVISOR_mmu_update] = 4,
+ [__HYPERVISOR_stack_switch] = 2,
+ [__HYPERVISOR_fpu_taskswitch] = 1,
+ [__HYPERVISOR_update_descriptor] = 2,
+ [__HYPERVISOR_update_va_mapping] = 3,
+ [__HYPERVISOR_mmuext_op] = 4,
+};
+
+static void print_debug_data(struct mc_buffer *b, struct mc_debug_data *mcdb,
+ int idx)
+{
+ unsigned int arg;
+ unsigned int opidx = mcdb->entries[idx].op & 0xff;
+ unsigned int pars = 0;
+
+ pr_err(" call %2d: op=%lu result=%ld caller=%pS ", idx + 1,
+ mcdb->entries[idx].op, b->entries[idx].result,
+ mcdb->caller[idx]);
+ if (opidx < ARRAY_SIZE(hpcpars))
+ pars = hpcpars[opidx];
+ if (pars) {
+ pr_cont("pars=");
+ for (arg = 0; arg < pars; arg++)
+ pr_cont("%lx ", mcdb->entries[idx].args[arg]);
+ }
+ if (mcdb->argsz[idx]) {
+ pr_cont("args=");
+ for (arg = 0; arg < mcdb->argsz[idx] / 8; arg++)
+ pr_cont("%lx ", mcdb->args[idx][arg]);
+ }
+ pr_cont("\n");
+}
+
void xen_mc_flush(void)
{
struct mc_buffer *b = this_cpu_ptr(&mc_buffer);
struct multicall_entry *mc;
+ struct mc_debug_data *mcdb = NULL;
int ret = 0;
unsigned long flags;
int i;
@@ -68,6 +156,12 @@ void xen_mc_flush(void)
trace_xen_mc_flush(b->mcidx, b->argidx, b->cbidx);
+ if (static_key_false(&mc_debug)) {
+ mcdb = get_mc_debug();
+ memcpy(mcdb->entries, b->entries,
+ b->mcidx * sizeof(struct multicall_entry));
+ }
+
switch (b->mcidx) {
case 0:
/* no-op */
@@ -79,39 +173,34 @@ void xen_mc_flush(void)
and just do the call directly. */
mc = &b->entries[0];
- mc->result = privcmd_call(mc->op,
- mc->args[0], mc->args[1], mc->args[2],
- mc->args[3], mc->args[4]);
+ mc->result = xen_single_call(mc->op, mc->args[0], mc->args[1],
+ mc->args[2], mc->args[3],
+ mc->args[4]);
ret = mc->result < 0;
break;
default:
-#if MC_DEBUG
- memcpy(b->debug, b->entries,
- b->mcidx * sizeof(struct multicall_entry));
-#endif
-
if (HYPERVISOR_multicall(b->entries, b->mcidx) != 0)
BUG();
for (i = 0; i < b->mcidx; i++)
if (b->entries[i].result < 0)
ret++;
+ }
-#if MC_DEBUG
- if (ret) {
- printk(KERN_ERR "%d multicall(s) failed: cpu %d\n",
- ret, smp_processor_id());
- dump_stack();
- for (i = 0; i < b->mcidx; i++) {
- printk(KERN_DEBUG " call %2d/%d: op=%lu arg=[%lx] result=%ld\t%pF\n",
- i+1, b->mcidx,
- b->debug[i].op,
- b->debug[i].args[0],
- b->entries[i].result,
- b->caller[i]);
+ if (WARN_ON(ret)) {
+ pr_err("%d of %d multicall(s) failed: cpu %d\n",
+ ret, b->mcidx, smp_processor_id());
+ for (i = 0; i < b->mcidx; i++) {
+ if (static_key_false(&mc_debug)) {
+ print_debug_data(b, mcdb, i);
+ } else if (b->entries[i].result < 0) {
+ pr_err(" call %2d: op=%lu arg=[%lx] result=%ld\n",
+ i + 1,
+ b->entries[i].op,
+ b->entries[i].args[0],
+ b->entries[i].result);
}
}
-#endif
}
b->mcidx = 0;
@@ -125,8 +214,6 @@ void xen_mc_flush(void)
b->cbidx = 0;
local_irq_restore(flags);
-
- WARN_ON(ret);
}
struct multicall_space __xen_mc_entry(size_t args)
@@ -149,9 +236,13 @@ struct multicall_space __xen_mc_entry(size_t args)
}
ret.mc = &b->entries[b->mcidx];
-#if MC_DEBUG
- b->caller[b->mcidx] = __builtin_return_address(0);
-#endif
+ if (static_key_false(&mc_debug)) {
+ struct mc_debug_data *mcdb = get_mc_debug();
+
+ mcdb->caller[b->mcidx] = __builtin_return_address(0);
+ mcdb->argsz[b->mcidx] = args;
+ mcdb->args[b->mcidx] = (unsigned long *)(&b->args[argidx]);
+ }
b->mcidx++;
ret.args = &b->args[argidx];
b->argidx = argidx + args;
generated by cgit (git 2.34.1) at 2025-12-25 12:07:13 +0000