Allow pausing and unpausing guests running on the host. Pausing a guest means that none of the VCPU threads are running KVM_RUN until they are unpaused.
The following API functions are added: void kvm__pause(void); void kvm__continue(void); void kvm__notify_paused(void); Signed-off-by: Sasha Levin <[email protected]> --- tools/kvm/include/kvm/kvm-cpu.h | 1 + tools/kvm/include/kvm/kvm.h | 4 +++ tools/kvm/kvm-cpu.c | 20 +++++++++++--- tools/kvm/kvm-run.c | 4 +- tools/kvm/kvm.c | 54 +++++++++++++++++++++++++++++++++++++++ 5 files changed, 76 insertions(+), 7 deletions(-) diff --git a/tools/kvm/include/kvm/kvm-cpu.h b/tools/kvm/include/kvm/kvm-cpu.h index b2b6fce..4d99246 100644 --- a/tools/kvm/include/kvm/kvm-cpu.h +++ b/tools/kvm/include/kvm/kvm-cpu.h @@ -23,6 +23,7 @@ struct kvm_cpu { struct kvm_msrs *msrs; /* dynamically allocated */ u8 is_running; + u8 paused; }; struct kvm_cpu *kvm_cpu__init(struct kvm *kvm, unsigned long cpu_id); diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h index 6a17362..d22a849 100644 --- a/tools/kvm/include/kvm/kvm.h +++ b/tools/kvm/include/kvm/kvm.h @@ -12,6 +12,7 @@ #define KVM_32BIT_GAP_START ((1ULL << 32) - KVM_32BIT_GAP_SIZE) #define SIGKVMEXIT (SIGRTMIN + 0) +#define SIGKVMPAUSE (SIGRTMIN + 1) struct kvm { int sys_fd; /* For system ioctls(), i.e. /dev/kvm */ @@ -50,6 +51,9 @@ bool kvm__emulate_io(struct kvm *kvm, u16 port, void *data, int direction, int s bool kvm__emulate_mmio(struct kvm *kvm, u64 phys_addr, u8 *data, u32 len, u8 is_write); bool kvm__register_mmio(u64 phys_addr, u64 phys_addr_len, void (*kvm_mmio_callback_fn)(u64 addr, u8 *data, u32 len, u8 is_write)); bool kvm__deregister_mmio(u64 phys_addr); +void kvm__pause(void); +void kvm__continue(void); +void kvm__notify_paused(void); /* * Debugging diff --git a/tools/kvm/kvm-cpu.c b/tools/kvm/kvm-cpu.c index de0591f..be0528b 100644 --- a/tools/kvm/kvm-cpu.c +++ b/tools/kvm/kvm-cpu.c @@ -383,11 +383,15 @@ void kvm_cpu__run(struct kvm_cpu *vcpu) die_perror("KVM_RUN failed"); } -static void kvm_cpu_exit_handler(int signum) +static void kvm_cpu_signal_handler(int signum) { - if (current_kvm_cpu->is_running) { - current_kvm_cpu->is_running = false; - pthread_kill(pthread_self(), SIGKVMEXIT); + if (signum == SIGKVMEXIT) { + if (current_kvm_cpu->is_running) { + current_kvm_cpu->is_running = false; + pthread_kill(pthread_self(), SIGKVMEXIT); + } + } else if (signum == SIGKVMPAUSE) { + current_kvm_cpu->paused = 1; } } @@ -400,12 +404,18 @@ int kvm_cpu__start(struct kvm_cpu *cpu) pthread_sigmask(SIG_BLOCK, &sigset, NULL); - signal(SIGKVMEXIT, kvm_cpu_exit_handler); + signal(SIGKVMEXIT, kvm_cpu_signal_handler); + signal(SIGKVMPAUSE, kvm_cpu_signal_handler); kvm_cpu__setup_cpuid(cpu); kvm_cpu__reset_vcpu(cpu); for (;;) { + if (cpu->paused) { + kvm__notify_paused(); + cpu->paused = 0; + } + kvm_cpu__run(cpu); switch (cpu->kvm_run->exit_reason) { diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c index 48b8e70..761ac0d 100644 --- a/tools/kvm/kvm-run.c +++ b/tools/kvm/kvm-run.c @@ -47,8 +47,8 @@ #define MIN_RAM_SIZE_MB (64ULL) #define MIN_RAM_SIZE_BYTE (MIN_RAM_SIZE_MB << MB_SHIFT) -static struct kvm *kvm; -static struct kvm_cpu *kvm_cpus[KVM_NR_CPUS]; +struct kvm *kvm; +struct kvm_cpu *kvm_cpus[KVM_NR_CPUS]; __thread struct kvm_cpu *current_kvm_cpu; static u64 ram_size; diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c index 1d756e0..54e3203 100644 --- a/tools/kvm/kvm.c +++ b/tools/kvm/kvm.c @@ -6,6 +6,8 @@ #include "kvm/interrupt.h" #include "kvm/mptable.h" #include "kvm/util.h" +#include "kvm/mutex.h" +#include "kvm/kvm-cpu.h" #include <linux/kvm.h> @@ -25,6 +27,7 @@ #include <stdio.h> #include <fcntl.h> #include <time.h> +#include <sys/eventfd.h> #define DEFINE_KVM_EXIT_REASON(reason) [reason] = #reason @@ -68,6 +71,11 @@ struct { { DEFINE_KVM_EXT(KVM_CAP_EXT_CPUID) }, }; +extern struct kvm *kvm; +extern struct kvm_cpu *kvm_cpus[KVM_NR_CPUS]; +static int pause_event; +static DEFINE_MUTEX(pause_lock); + static bool kvm__supports_extension(struct kvm *kvm, unsigned int extension) { int ret; @@ -575,3 +583,49 @@ void kvm__dump_mem(struct kvm *kvm, unsigned long addr, unsigned long size) p[n + 4], p[n + 5], p[n + 6], p[n + 7]); } } + +void kvm__pause(void) +{ + int i, paused_vcpus = 0; + + /* Check if the guest is running */ + if (!kvm_cpus[0] || kvm_cpus[0]->thread == 0) + return; + + mutex_lock(&pause_lock); + + pause_event = eventfd(0, 0); + if (pause_event < 0) + die("Failed creating pause notification event"); + for (i = 0; i < kvm->nrcpus; i++) + pthread_kill(kvm_cpus[i]->thread, SIGKVMPAUSE); + + while (paused_vcpus < kvm->nrcpus) { + u64 cur_read; + + if (read(pause_event, &cur_read, sizeof(cur_read)) < 0) + die("Failed reading pause event"); + paused_vcpus += cur_read; + } + close(pause_event); +} + +void kvm__continue(void) +{ + /* Check if the guest is running */ + if (!kvm_cpus[0] || kvm_cpus[0]->thread == 0) + return; + + mutex_unlock(&pause_lock); +} + +void kvm__notify_paused(void) +{ + u64 p = 1; + + if (write(pause_event, &p, sizeof(p)) < 0) + die("Failed notifying of paused VCPU."); + + mutex_lock(&pause_lock); + mutex_unlock(&pause_lock); +} -- 1.7.5.rc3 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
