Hi. This is a proposal for reducing the impact of kvm functions in core qemu
code. This is by all means not ready, but I felt like posting it, so a
discussion
on it could follow.
The idea in this patch is to replace the specific kvm details from core qemu
files
like vl.c, with driver_yyy() functions. When kvm is not running, those
functions would
just return (most of time), absolutely reducing the impact of kvm code.
As I wanted to test it, in this patch I changed the kvm functions to be called
driver_yyy(),
but that's not my final goal. I intend to use a function pointer schema,
similar to what the linux
kernel already do for a lot of its subsystem, to isolate the changes.
Comments deeply welcome.
---
qemu/exec.c | 11 +--
qemu/gdbstub.c | 8 +-
qemu/hw/vmport.c | 6 +-
qemu/monitor.c | 3 +-
qemu/qemu-kvm.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
qemu/qemu-kvm.h | 1 +
qemu/vl.c | 187 +++++-------------------------------------------
7 files changed, 239 insertions(+), 187 deletions(-)
diff --git a/qemu/exec.c b/qemu/exec.c
index b82d26d..7a16c78 100644
--- a/qemu/exec.c
+++ b/qemu/exec.c
@@ -1150,8 +1150,7 @@ int cpu_breakpoint_insert(CPUState *env, target_ulong pc)
return -1;
env->breakpoints[env->nb_breakpoints++] = pc;
- if (kvm_enabled())
- kvm_update_debugger(env);
+ driver_update_debugger(env);
breakpoint_invalidate(env, pc);
return 0;
@@ -1175,8 +1174,7 @@ int cpu_breakpoint_remove(CPUState *env, target_ulong pc)
if (i < env->nb_breakpoints)
env->breakpoints[i] = env->breakpoints[env->nb_breakpoints];
- if (kvm_enabled())
- kvm_update_debugger(env);
+ driver_update_debugger(env);
breakpoint_invalidate(env, pc);
return 0;
@@ -1196,8 +1194,7 @@ void cpu_single_step(CPUState *env, int enabled)
/* XXX: only flush what is necessary */
tb_flush(env);
}
- if (kvm_enabled())
- kvm_update_debugger(env);
+ driver_update_debugger(env);
#endif
}
@@ -1246,7 +1243,7 @@ void cpu_interrupt(CPUState *env, int mask)
env->interrupt_request |= mask;
if (kvm_enabled() && !qemu_kvm_irqchip_in_kernel())
- kvm_update_interrupt_request(env);
+ kvm_update_interrupt_request(env);
/* if the cpu is currently executing code, we must unlink it and
all the potentially executing TB */
diff --git a/qemu/gdbstub.c b/qemu/gdbstub.c
index 2252084..c574686 100644
--- a/qemu/gdbstub.c
+++ b/qemu/gdbstub.c
@@ -895,7 +895,7 @@ static int gdb_handle_packet(GDBState *s, CPUState *env,
const char *line_buf)
#if defined(TARGET_I386)
env->eip = addr;
if (kvm_enabled())
- kvm_load_registers(env);
+ driver_load_registers(env);
#elif defined (TARGET_PPC)
env->nip = addr;
#elif defined (TARGET_SPARC)
@@ -923,7 +923,7 @@ static int gdb_handle_packet(GDBState *s, CPUState *env,
const char *line_buf)
#if defined(TARGET_I386)
env->eip = addr;
if (kvm_enabled())
- kvm_load_registers(env);
+ driver_load_registers(env);
#elif defined (TARGET_PPC)
env->nip = addr;
#elif defined (TARGET_SPARC)
@@ -976,7 +976,7 @@ static int gdb_handle_packet(GDBState *s, CPUState *env,
const char *line_buf)
break;
case 'g':
if (kvm_enabled())
- kvm_save_registers(env);
+ driver_save_registers(env);
reg_size = cpu_gdb_read_registers(env, mem_buf);
memtohex(buf, mem_buf, reg_size);
put_packet(s, buf);
@@ -987,7 +987,7 @@ static int gdb_handle_packet(GDBState *s, CPUState *env,
const char *line_buf)
hextomem((uint8_t *)registers, p, len);
cpu_gdb_write_registers(env, mem_buf, len);
if (kvm_enabled())
- kvm_load_registers(env);
+ driver_load_registers(env);
put_packet(s, "OK");
break;
case 'm':
diff --git a/qemu/hw/vmport.c b/qemu/hw/vmport.c
index c09227d..a519152 100644
--- a/qemu/hw/vmport.c
+++ b/qemu/hw/vmport.c
@@ -59,8 +59,7 @@ static uint32_t vmport_ioport_read(void *opaque, uint32_t
addr)
uint32_t eax;
uint32_t ret;
- if (kvm_enabled())
- kvm_save_registers(s->env);
+ driver_save_registers(s->env);
eax = s->env->regs[R_EAX];
if (eax != VMPORT_MAGIC)
@@ -77,8 +76,7 @@ static uint32_t vmport_ioport_read(void *opaque, uint32_t
addr)
ret = s->func[command](s->opaque[command], addr);
- if (kvm_enabled())
- kvm_load_registers(s->env);
+ driver_load_registers(s->env);
return ret;
}
diff --git a/qemu/monitor.c b/qemu/monitor.c
index 4ee0b19..bd538d9 100644
--- a/qemu/monitor.c
+++ b/qemu/monitor.c
@@ -286,8 +286,7 @@ static CPUState *mon_get_cpu(void)
mon_set_cpu(0);
}
- if (kvm_enabled())
- kvm_save_registers(mon_cpu);
+ driver_save_registers(mon_cpu);
return mon_cpu;
}
diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c
index 45fddd3..f3a7758 100644
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -20,6 +20,11 @@ int kvm_irqchip = 1;
#include <pthread.h>
#include <sys/utsname.h>
#include <sys/syscall.h>
+#include <sys/mman.h>
+
+int hpagesize = 0;
+unsigned int kvm_shadow_memory = 0;
+extern char *mem_path;
extern void perror(const char *s);
@@ -114,16 +119,16 @@ static int pre_kvm_run(void *opaque, int vcpu)
return 0;
}
-void kvm_load_registers(CPUState *env)
+void driver_load_registers(CPUState *env)
{
if (kvm_enabled())
kvm_arch_load_regs(env);
}
-void kvm_save_registers(CPUState *env)
+void driver_save_registers(CPUState *env)
{
if (kvm_enabled())
- kvm_arch_save_regs(env);
+ kvm_arch_save_regs(env);
}
int kvm_cpu_exec(CPUState *env)
@@ -628,6 +633,11 @@ int kvm_update_debugger(CPUState *env)
return kvm_guest_debug(kvm_context, env->cpu_index, &dbg);
}
+int driver_update_debugger(CPUState *env)
+{
+ if (kvm_enabled())
+ kvm_update_debugger(env);
+}
/*
* dirty pages logging
@@ -774,3 +784,197 @@ void kvm_cpu_destroy_phys_mem(target_phys_addr_t
start_addr,
{
kvm_destroy_phys_mem(kvm_context, start_addr, size);
}
+
+/* FIXME: make it all beautiful when kvm is off, make room for other
hypervisors, etc */
+
+void decorate_application_name(char *appname, int max_len)
+{
+ if (kvm_enabled())
+ {
+ int remain = max_len - strlen(appname) - 1;
+
+ if (remain > 0)
+ strncat(appname, "/KVM", remain);
+ }
+}
+
+static int gethugepagesize(void)
+{
+ int ret, fd;
+ char buf[4096];
+ char *needle = "Hugepagesize:";
+ char *size;
+ unsigned long hugepagesize;
+
+ fd = open("/proc/meminfo", O_RDONLY);
+ if (fd < 0) {
+ perror("open");
+ exit(0);
+ }
+
+ ret = read(fd, buf, sizeof(buf));
+ if (ret < 0) {
+ perror("read");
+ exit(0);
+ }
+
+ size = strstr(buf, needle);
+ if (!size)
+ return 0;
+ size += strlen(needle);
+ hugepagesize = strtol(size, NULL, 0);
+ return hugepagesize;
+}
+
+
+void *alloc_mem_area(unsigned long memory, const char *path)
+{
+ char *filename;
+ void *area;
+ int fd;
+
+ if (asprintf(&filename, "%s/kvm.XXXXXX", path) == -1)
+ return NULL;
+
+ hpagesize = gethugepagesize() * 1024;
+ if (!hpagesize)
+ return NULL;
+
+ fd = mkstemp(filename);
+ if (fd < 0) {
+ perror("mkstemp");
+ free(filename);
+ return NULL;
+ }
+ unlink(filename);
+ free(filename);
+
+ memory = (memory+hpagesize-1) & ~(hpagesize-1);
+
+ if (ftruncate(fd, memory) == -1) {
+ perror("ftruncate");
+ close(fd);
+ return NULL;
+ }
+
+ area = mmap(0, memory, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
+ if (area == MAP_FAILED) {
+ perror("mmap");
+ close(fd);
+ return NULL;
+ }
+
+ return area;
+}
+
+void *qemu_alloc_physram(unsigned long memory)
+{
+ void *area = NULL;
+
+ if (mem_path)
+ area = alloc_mem_area(memory, mem_path);
+ if (!area)
+ area = qemu_vmalloc(memory);
+
+ return area;
+}
+
+
+void driver_cpu_save_end(QEMUFile *f, CPUState *env)
+{
+ int i;
+ if (kvm_enabled()) {
+ for (i = 0; i < NR_IRQ_WORDS ; i++) {
+ qemu_put_be32s(f, &env->kvm_interrupt_bitmap[i]);
+ }
+ qemu_put_be64s(f, &env->tsc);
+ }
+}
+
+int driver_cpu_load(QEMUFile *f, CPUState *env, int version_id)
+{
+ int i;
+ if (kvm_enabled()) {
+ /* when in-kernel irqchip is used, HF_HALTED_MASK causes deadlock
+ because no userspace IRQs will ever clear this flag */
+ env->hflags &= ~HF_HALTED_MASK;
+ for (i = 0; i < NR_IRQ_WORDS ; i++) {
+ qemu_get_be32s(f, &env->kvm_interrupt_bitmap[i]);
+ }
+ qemu_get_be64s(f, &env->tsc);
+ driver_load_registers(env);
+ }
+ return 0;
+}
+
+int driver_allowed_page(target_ulong addr)
+{
+ if (kvm_enabled() && (addr>=0xa0000) && (addr<0xc0000)) /* do not access
video-addresses */
+ return 0;
+ return 1;
+}
+
+int driver_main_loop(void)
+{
+ if (kvm_enabled()) {
+ kvm_main_loop();
+ cpu_disable_ticks();
+ return 0;
+ }
+ return -1;
+}
+
+void driver_init_context(void)
+{
+#if USE_KVM
+ if (kvm_enabled()) {
+ if (kvm_qemu_init() < 0) {
+ extern int kvm_allowed;
+ fprintf(stderr, "Could not initialize KVM, will disable KVM
support\n");
+#ifdef NO_CPU_EMULATION
+ fprintf(stderr, "Compiled with --disable-cpu-emulation,
exiting.\n");
+ exit(1);
+#endif
+ kvm_allowed = 0;
+ }
+ }
+#endif
+}
+
+int driver_init()
+{
+#if defined(TARGET_I386) || defined(TARGET_X86_64)
+#define KVM_EXTRA_PAGES 3
+#else
+#define KVM_EXTRA_PAGES 0
+#endif
+ if (kvm_enabled()) {
+ phys_ram_size += KVM_EXTRA_PAGES * TARGET_PAGE_SIZE;
+ if (kvm_qemu_create_context() < 0) {
+ fprintf(stderr, "Could not create KVM context\n");
+ exit(1);
+ }
+#ifdef KVM_CAP_USER_MEMORY
+ {
+ int ret;
+
+ ret = kvm_qemu_check_extension(KVM_CAP_USER_MEMORY);
+ if (ret) {
+ phys_ram_base = qemu_alloc_physram(phys_ram_size);
+ if (!phys_ram_base) {
+ fprintf(stderr, "Could not allocate physical memory\n");
+ exit(1);
+ }
+ }
+ }
+#endif
+ return 1;
+ }
+ return 0;
+}
+
+void driver_smp_init(void)
+{
+ if (kvm_enabled())
+ kvm_init_ap();
+}
diff --git a/qemu/qemu-kvm.h b/qemu/qemu-kvm.h
index 8e45f30..7953f4a 100644
--- a/qemu/qemu-kvm.h
+++ b/qemu/qemu-kvm.h
@@ -81,6 +81,7 @@ int handle_powerpc_dcr_write(int vcpu,uint32_t dcrn, uint32_t
data);
extern int kvm_allowed;
extern kvm_context_t kvm_context;
+extern unsigned int kvm_shadow_memory;
#define kvm_enabled() (kvm_allowed)
#define qemu_kvm_irqchip_in_kernel() kvm_irqchip_in_kernel(kvm_context)
diff --git a/qemu/vl.c b/qemu/vl.c
index a59f71c..4df410f 100644
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -234,9 +234,7 @@ int nb_option_roms;
int semihosting_enabled = 0;
int autostart = 1;
int time_drift_fix = 0;
-unsigned int kvm_shadow_memory = 0;
const char *mem_path = NULL;
-int hpagesize = 0;
const char *cpu_vendor_string;
#ifdef TARGET_ARM
int old_param = 0;
@@ -259,17 +257,6 @@ static int event_pending = 1;
#define TFR(expr) do { if ((expr) != -1) break; } while (errno == EINTR)
-void decorate_application_name(char *appname, int max_len)
-{
- if (kvm_enabled())
- {
- int remain = max_len - strlen(appname) - 1;
-
- if (remain > 0)
- strncat(appname, "/KVM", remain);
- }
-}
-
/***********************************************************/
/* x86 ISA bus support */
@@ -6544,8 +6531,7 @@ void cpu_save(QEMUFile *f, void *opaque)
uint32_t hflags;
int i;
- if (kvm_enabled())
- kvm_save_registers(env);
+ driver_save_registers(env);
for(i = 0; i < CPU_NB_REGS; i++)
qemu_put_betls(f, &env->regs[i]);
@@ -6632,12 +6618,7 @@ void cpu_save(QEMUFile *f, void *opaque)
#endif
qemu_put_be32s(f, &env->smbase);
- if (kvm_enabled()) {
- for (i = 0; i < NR_IRQ_WORDS ; i++) {
- qemu_put_be32s(f, &env->kvm_interrupt_bitmap[i]);
- }
- qemu_put_be64s(f, &env->tsc);
- }
+ driver_cpu_save_end(f, env);
}
#ifdef USE_X86LDOUBLE
@@ -6780,17 +6761,7 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id)
/* XXX: compute hflags from scratch, except for CPL and IIF */
env->hflags = hflags;
tlb_flush(env, 1);
- if (kvm_enabled()) {
- /* when in-kernel irqchip is used, HF_HALTED_MASK causes deadlock
- because no userspace IRQs will ever clear this flag */
- env->hflags &= ~HF_HALTED_MASK;
- for (i = 0; i < NR_IRQ_WORDS ; i++) {
- qemu_get_be32s(f, &env->kvm_interrupt_bitmap[i]);
- }
- qemu_get_be64s(f, &env->tsc);
- kvm_load_registers(env);
- }
- return 0;
+ return driver_cpu_load(f, opaque, version_id);
}
#elif defined(TARGET_PPC)
@@ -7126,7 +7097,7 @@ static int ram_load_v1(QEMUFile *f, void *opaque)
if (qemu_get_be32(f) != phys_ram_size)
return -EINVAL;
for(i = 0; i < phys_ram_size; i+= TARGET_PAGE_SIZE) {
- if (kvm_enabled() && (i>=0xa0000) && (i<0xc0000)) /* do not access
video-addresses */
+ if (!driver_allowed_page(i))
continue;
ret = ram_get_page(f, phys_ram_base + i, TARGET_PAGE_SIZE);
if (ret)
@@ -7262,7 +7233,7 @@ static void ram_save_live(QEMUFile *f, void *opaque)
target_ulong addr;
for (addr = 0; addr < phys_ram_size; addr += TARGET_PAGE_SIZE) {
- if (kvm_enabled() && (addr>=0xa0000) && (addr<0xc0000)) /* do not
access video-addresses */
+ if (!driver_allowed_page(addr))
continue;
if (cpu_physical_memory_get_dirty(addr, MIGRATION_DIRTY_FLAG)) {
qemu_put_be32(f, addr);
@@ -7282,7 +7253,7 @@ static void ram_save_static(QEMUFile *f, void *opaque)
if (ram_compress_open(s, f) < 0)
return;
for(i = 0; i < phys_ram_size; i+= BDRV_HASH_BLOCK_SIZE) {
- if (kvm_enabled() && (i>=0xa0000) && (i<0xc0000)) /* do not access
video-addresses */
+ if (!driver_allowed_page(i))
continue;
#if 0
if (tight_savevm_enabled) {
@@ -7355,7 +7326,7 @@ static int ram_load_static(QEMUFile *f, void *opaque)
if (ram_decompress_open(s, f) < 0)
return -EINVAL;
for(i = 0; i < phys_ram_size; i+= BDRV_HASH_BLOCK_SIZE) {
- if (kvm_enabled() && (i>=0xa0000) && (i<0xc0000)) /* do not access
video-addresses */
+ if (!driver_allowed_page(i))
continue;
if (ram_decompress_buf(s, buf, 1) < 0) {
fprintf(stderr, "Error while reading ram block header\n");
@@ -7846,6 +7817,11 @@ void main_loop_wait(int timeout)
}
+int driver_enabled(void)
+{
+ return 1;
+}
+
static int main_loop(void)
{
int ret, timeout;
@@ -7854,12 +7830,8 @@ static int main_loop(void)
#endif
CPUState *env;
-
- if (kvm_enabled()) {
- kvm_main_loop();
- cpu_disable_ticks();
- return 0;
- }
+ if (driver_enabled() && (ret = driver_main_loop() < 0))
+ return ret;
cur_cpu = first_cpu;
next_cpu = cur_cpu->next_cpu ?: first_cpu;
@@ -7902,15 +7874,16 @@ static int main_loop(void)
if (reset_requested) {
reset_requested = 0;
qemu_system_reset();
- if (kvm_enabled())
- kvm_load_registers(env);
+ driver_load_registers();
ret = EXCP_INTERRUPT;
}
+
if (powerdown_requested) {
powerdown_requested = 0;
qemu_system_powerdown();
ret = EXCP_INTERRUPT;
}
+
if (ret == EXCP_DEBUG) {
vm_stop(EXCP_DEBUG);
}
@@ -8564,87 +8537,6 @@ void qemu_get_launch_info(int *argc, char ***argv, int
*opt_daemonize, const cha
*opt_incoming = incoming;
}
-
-static int gethugepagesize(void)
-{
- int ret, fd;
- char buf[4096];
- char *needle = "Hugepagesize:";
- char *size;
- unsigned long hugepagesize;
-
- fd = open("/proc/meminfo", O_RDONLY);
- if (fd < 0) {
- perror("open");
- exit(0);
- }
-
- ret = read(fd, buf, sizeof(buf));
- if (ret < 0) {
- perror("read");
- exit(0);
- }
-
- size = strstr(buf, needle);
- if (!size)
- return 0;
- size += strlen(needle);
- hugepagesize = strtol(size, NULL, 0);
- return hugepagesize;
-}
-
-void *alloc_mem_area(unsigned long memory, const char *path)
-{
- char *filename;
- void *area;
- int fd;
-
- if (asprintf(&filename, "%s/kvm.XXXXXX", path) == -1)
- return NULL;
-
- hpagesize = gethugepagesize() * 1024;
- if (!hpagesize)
- return NULL;
-
- fd = mkstemp(filename);
- if (fd < 0) {
- perror("mkstemp");
- free(filename);
- return NULL;
- }
- unlink(filename);
- free(filename);
-
- memory = (memory+hpagesize-1) & ~(hpagesize-1);
-
- if (ftruncate(fd, memory) == -1) {
- perror("ftruncate");
- close(fd);
- return NULL;
- }
-
- area = mmap(0, memory, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
- if (area == MAP_FAILED) {
- perror("mmap");
- close(fd);
- return NULL;
- }
-
- return area;
-}
-
-void *qemu_alloc_physram(unsigned long memory)
-{
- void *area = NULL;
-
- if (mem_path)
- area = alloc_mem_area(memory, mem_path);
- if (!area)
- area = qemu_vmalloc(memory);
-
- return area;
-}
-
int main(int argc, char **argv)
{
#ifdef CONFIG_GDBSTUB
@@ -9355,19 +9247,7 @@ int main(int argc, char **argv)
}
#endif
-#if USE_KVM
- if (kvm_enabled()) {
- if (kvm_qemu_init() < 0) {
- extern int kvm_allowed;
- fprintf(stderr, "Could not initialize KVM, will disable KVM
support\n");
-#ifdef NO_CPU_EMULATION
- fprintf(stderr, "Compiled with --disable-cpu-emulation,
exiting.\n");
- exit(1);
-#endif
- kvm_allowed = 0;
- }
- }
-#endif
+ driver_init_context();
if (pid_file && qemu_create_pidfile(pid_file) != 0) {
if (daemonize) {
@@ -9463,33 +9343,7 @@ int main(int argc, char **argv)
/* init the memory */
phys_ram_size = ram_size + vga_ram_size + MAX_BIOS_SIZE;
- /* Initialize kvm */
-#if defined(TARGET_I386) || defined(TARGET_X86_64)
-#define KVM_EXTRA_PAGES 3
-#else
-#define KVM_EXTRA_PAGES 0
-#endif
- if (kvm_enabled()) {
- phys_ram_size += KVM_EXTRA_PAGES * TARGET_PAGE_SIZE;
- if (kvm_qemu_create_context() < 0) {
- fprintf(stderr, "Could not create KVM context\n");
- exit(1);
- }
-#ifdef KVM_CAP_USER_MEMORY
-{
- int ret;
-
- ret = kvm_qemu_check_extension(KVM_CAP_USER_MEMORY);
- if (ret) {
- phys_ram_base = qemu_alloc_physram(phys_ram_size);
- if (!phys_ram_base) {
- fprintf(stderr, "Could not allocate physical memory\n");
- exit(1);
- }
- }
-}
-#endif
- } else {
+ if (!driver_init()) {
phys_ram_base = qemu_vmalloc(phys_ram_size);
if (!phys_ram_base) {
fprintf(stderr, "Could not allocate physical memory\n");
@@ -9637,8 +9491,7 @@ int main(int argc, char **argv)
qemu_mod_timer(display_state.gui_timer, qemu_get_clock(rt_clock));
}
- if (kvm_enabled())
- kvm_init_ap();
+ driver_smp_init();
#ifdef CONFIG_GDBSTUB
if (use_gdbstub) {
--
1.5.0.6
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