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From: Peter Xu <peterx@redhat.com>
To: Julia Suvorova <jusual@redhat.com>
Cc: qemu-devel@nongnu.org, "Paolo Bonzini" <pbonzini@redhat.com>,
	"Marcelo Tosatti" <mtosatti@redhat.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Song Gao" <gaosong@loongson.cn>,
	"Alistair Francis" <alistair.francis@wdc.com>,
	"Daniel Henrique Barboza" <danielhb413@gmail.com>,
	"Christian Borntraeger" <borntraeger@linux.ibm.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>
Subject: Re: [PATCH 1/2] kvm: Allow kvm_arch_get/put_registers to accept Error**
Date: Wed, 25 Sep 2024 14:53:48 -0400	[thread overview]
Message-ID: <ZvRcPBMYLlczv-3P@x1n> (raw)
In-Reply-To: <20240925153625.183600-2-jusual@redhat.com>

On Wed, Sep 25, 2024 at 05:36:22PM +0200, Julia Suvorova wrote:
> This is necessary to provide discernible error messages to the caller.
> 
> Signed-off-by: Julia Suvorova <jusual@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

One nitpick below:

> ---
>  accel/kvm/kvm-all.c        | 41 +++++++++++++++++++++++++++++---------
>  include/sysemu/kvm.h       |  4 ++--
>  target/arm/kvm.c           |  4 ++--
>  target/i386/kvm/kvm.c      |  4 ++--
>  target/loongarch/kvm/kvm.c |  4 ++--
>  target/mips/kvm.c          |  4 ++--
>  target/ppc/kvm.c           |  2 +-
>  target/riscv/kvm/kvm-cpu.c |  4 ++--
>  target/s390x/kvm/kvm.c     |  4 ++--
>  9 files changed, 47 insertions(+), 24 deletions(-)
> 
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index fe4cd721d9..19e09067b3 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -2762,9 +2762,15 @@ void kvm_flush_coalesced_mmio_buffer(void)
>  static void do_kvm_cpu_synchronize_state(CPUState *cpu, run_on_cpu_data arg)
>  {
>      if (!cpu->vcpu_dirty && !kvm_state->guest_state_protected) {
> -        int ret = kvm_arch_get_registers(cpu);
> +        Error *err = NULL;
> +        int ret = kvm_arch_get_registers(cpu, &err);
>          if (ret) {
> -            error_report("Failed to get registers: %s", strerror(-ret));
> +            if (err) {
> +                error_report_err(err);
> +            } else {
> +                error_report("Failed to get registers: %s", strerror(-ret));
> +            }
> +
>              cpu_dump_state(cpu, stderr, CPU_DUMP_CODE);
>              vm_stop(RUN_STATE_INTERNAL_ERROR);
>          }
> @@ -2782,9 +2788,15 @@ void kvm_cpu_synchronize_state(CPUState *cpu)
>  
>  static void do_kvm_cpu_synchronize_post_reset(CPUState *cpu, run_on_cpu_data arg)
>  {
> -    int ret = kvm_arch_put_registers(cpu, KVM_PUT_RESET_STATE);
> +    Error *err = NULL;
> +    int ret = kvm_arch_put_registers(cpu, KVM_PUT_RESET_STATE, &err);
>      if (ret) {
> -        error_report("Failed to put registers after reset: %s", strerror(-ret));
> +        if (err) {
> +            error_reportf_err(err, "Restoring resisters after reset");

IMO it'll be nice to use the same error report pattern, either
error_report_err() or error_reportf_err() for all the four call sites.

If to use error_reportf_err(), better add comma at the end (e.g. "PREFIX: "
instead of "PREFIX") to make the print looks slightly better.

Thanks!

> +        } else {
> +            error_report("Failed to put registers after reset: %s",
> +                         strerror(-ret));
> +        }
>          cpu_dump_state(cpu, stderr, CPU_DUMP_CODE);
>          vm_stop(RUN_STATE_INTERNAL_ERROR);
>      }
> @@ -2799,9 +2811,15 @@ void kvm_cpu_synchronize_post_reset(CPUState *cpu)
>  
>  static void do_kvm_cpu_synchronize_post_init(CPUState *cpu, run_on_cpu_data arg)
>  {
> -    int ret = kvm_arch_put_registers(cpu, KVM_PUT_FULL_STATE);
> +    Error *err = NULL;
> +    int ret = kvm_arch_put_registers(cpu, KVM_PUT_FULL_STATE, &err);
>      if (ret) {
> -        error_report("Failed to put registers after init: %s", strerror(-ret));
> +        if (err) {
> +            error_reportf_err(err, "Putting registers after init");
> +        } else {
> +            error_report("Failed to put registers after init: %s",
> +                         strerror(-ret));
> +        }
>          exit(1);
>      }
>  
> @@ -2991,10 +3009,15 @@ int kvm_cpu_exec(CPUState *cpu)
>          MemTxAttrs attrs;
>  
>          if (cpu->vcpu_dirty) {
> -            ret = kvm_arch_put_registers(cpu, KVM_PUT_RUNTIME_STATE);
> +            Error *err = NULL;
> +            ret = kvm_arch_put_registers(cpu, KVM_PUT_RUNTIME_STATE, &err);
>              if (ret) {
> -                error_report("Failed to put registers after init: %s",
> -                             strerror(-ret));
> +                if (err) {
> +                    error_reportf_err(err, "Putting registers after init");
> +                } else {
> +                    error_report("Failed to put registers after init: %s",
> +                                 strerror(-ret));
> +                }
>                  ret = -1;
>                  break;
>              }
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 613d3f7581..c3a60b2890 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -359,7 +359,7 @@ int kvm_arch_handle_exit(CPUState *cpu, struct kvm_run *run);
>  
>  int kvm_arch_process_async_events(CPUState *cpu);
>  
> -int kvm_arch_get_registers(CPUState *cpu);
> +int kvm_arch_get_registers(CPUState *cpu, Error **errp);
>  
>  /* state subset only touched by the VCPU itself during runtime */
>  #define KVM_PUT_RUNTIME_STATE   1
> @@ -368,7 +368,7 @@ int kvm_arch_get_registers(CPUState *cpu);
>  /* full state set, modified during initialization or on vmload */
>  #define KVM_PUT_FULL_STATE      3
>  
> -int kvm_arch_put_registers(CPUState *cpu, int level);
> +int kvm_arch_put_registers(CPUState *cpu, int level, Error **errp);
>  
>  int kvm_arch_get_default_type(MachineState *ms);
>  
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index 849e2e21b3..f1f1b5b375 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -2042,7 +2042,7 @@ static int kvm_arch_put_sve(CPUState *cs)
>      return 0;
>  }
>  
> -int kvm_arch_put_registers(CPUState *cs, int level)
> +int kvm_arch_put_registers(CPUState *cs, int level, Error **errp)
>  {
>      uint64_t val;
>      uint32_t fpr;
> @@ -2226,7 +2226,7 @@ static int kvm_arch_get_sve(CPUState *cs)
>      return 0;
>  }
>  
> -int kvm_arch_get_registers(CPUState *cs)
> +int kvm_arch_get_registers(CPUState *cs, Error **errp)
>  {
>      uint64_t val;
>      unsigned int el;
> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
> index ada581c5d6..039ed08825 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -5118,7 +5118,7 @@ static int kvm_get_nested_state(X86CPU *cpu)
>      return ret;
>  }
>  
> -int kvm_arch_put_registers(CPUState *cpu, int level)
> +int kvm_arch_put_registers(CPUState *cpu, int level, Error **errp)
>  {
>      X86CPU *x86_cpu = X86_CPU(cpu);
>      int ret;
> @@ -5206,7 +5206,7 @@ int kvm_arch_put_registers(CPUState *cpu, int level)
>      return 0;
>  }
>  
> -int kvm_arch_get_registers(CPUState *cs)
> +int kvm_arch_get_registers(CPUState *cs, Error **errp)
>  {
>      X86CPU *cpu = X86_CPU(cs);
>      int ret;
> diff --git a/target/loongarch/kvm/kvm.c b/target/loongarch/kvm/kvm.c
> index 4786cd5efa..30ec16025d 100644
> --- a/target/loongarch/kvm/kvm.c
> +++ b/target/loongarch/kvm/kvm.c
> @@ -588,7 +588,7 @@ static int kvm_loongarch_put_cpucfg(CPUState *cs)
>      return ret;
>  }
>  
> -int kvm_arch_get_registers(CPUState *cs)
> +int kvm_arch_get_registers(CPUState *cs, Error **errp)
>  {
>      int ret;
>  
> @@ -616,7 +616,7 @@ int kvm_arch_get_registers(CPUState *cs)
>      return ret;
>  }
>  
> -int kvm_arch_put_registers(CPUState *cs, int level)
> +int kvm_arch_put_registers(CPUState *cs, int level, Error **errp)
>  {
>      int ret;
>  
> diff --git a/target/mips/kvm.c b/target/mips/kvm.c
> index a631ab544f..a98798c669 100644
> --- a/target/mips/kvm.c
> +++ b/target/mips/kvm.c
> @@ -1172,7 +1172,7 @@ static int kvm_mips_get_cp0_registers(CPUState *cs)
>      return ret;
>  }
>  
> -int kvm_arch_put_registers(CPUState *cs, int level)
> +int kvm_arch_put_registers(CPUState *cs, int level, Error **errp)
>  {
>      CPUMIPSState *env = cpu_env(cs);
>      struct kvm_regs regs;
> @@ -1207,7 +1207,7 @@ int kvm_arch_put_registers(CPUState *cs, int level)
>      return ret;
>  }
>  
> -int kvm_arch_get_registers(CPUState *cs)
> +int kvm_arch_get_registers(CPUState *cs, Error **errp)
>  {
>      CPUMIPSState *env = cpu_env(cs);
>      int ret = 0;
> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> index 907dba60d1..a361d9d23c 100644
> --- a/target/ppc/kvm.c
> +++ b/target/ppc/kvm.c
> @@ -900,7 +900,7 @@ int kvmppc_put_books_sregs(PowerPCCPU *cpu)
>      return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_SREGS, &sregs);
>  }
>  
> -int kvm_arch_put_registers(CPUState *cs, int level)
> +int kvm_arch_put_registers(CPUState *cs, int level, Error **errp)
>  {
>      PowerPCCPU *cpu = POWERPC_CPU(cs);
>      CPUPPCState *env = &cpu->env;
> diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
> index f6e3156b8d..2bfb112be0 100644
> --- a/target/riscv/kvm/kvm-cpu.c
> +++ b/target/riscv/kvm/kvm-cpu.c
> @@ -1192,7 +1192,7 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
>      KVM_CAP_LAST_INFO
>  };
>  
> -int kvm_arch_get_registers(CPUState *cs)
> +int kvm_arch_get_registers(CPUState *cs, Error **errp)
>  {
>      int ret = 0;
>  
> @@ -1237,7 +1237,7 @@ int kvm_riscv_sync_mpstate_to_kvm(RISCVCPU *cpu, int state)
>      return 0;
>  }
>  
> -int kvm_arch_put_registers(CPUState *cs, int level)
> +int kvm_arch_put_registers(CPUState *cs, int level, Error **errp)
>  {
>      int ret = 0;
>  
> diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
> index 94181d9281..8ffe0159d8 100644
> --- a/target/s390x/kvm/kvm.c
> +++ b/target/s390x/kvm/kvm.c
> @@ -472,7 +472,7 @@ static int can_sync_regs(CPUState *cs, int regs)
>  #define KVM_SYNC_REQUIRED_REGS (KVM_SYNC_GPRS | KVM_SYNC_ACRS | \
>                                  KVM_SYNC_CRS | KVM_SYNC_PREFIX)
>  
> -int kvm_arch_put_registers(CPUState *cs, int level)
> +int kvm_arch_put_registers(CPUState *cs, int level, Error **errp)
>  {
>      CPUS390XState *env = cpu_env(cs);
>      struct kvm_fpu fpu = {};
> @@ -598,7 +598,7 @@ int kvm_arch_put_registers(CPUState *cs, int level)
>      return 0;
>  }
>  
> -int kvm_arch_get_registers(CPUState *cs)
> +int kvm_arch_get_registers(CPUState *cs, Error **errp)
>  {
>      CPUS390XState *env = cpu_env(cs);
>      struct kvm_fpu fpu;
> -- 
> 2.45.0
> 

-- 
Peter Xu



  reply	other threads:[~2024-09-25 18:54 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-25 15:36 [PATCH 0/2] kvm: Improve register failure reports for migration Julia Suvorova
2024-09-25 15:36 ` [PATCH 1/2] kvm: Allow kvm_arch_get/put_registers to accept Error** Julia Suvorova
2024-09-25 18:53   ` Peter Xu [this message]
2024-09-26 11:57     ` Julia Suvorova
2024-09-25 15:36 ` [PATCH 2/2] target/i386/kvm: Report which action failed in kvm_arch_put/get_registers Julia Suvorova
2024-09-25 18:54   ` Peter Xu

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