Re: [Qemu-devel] [PATCH 11/13] spapr: check for the activation of the KVM IRQ device

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jan 07, 2019 at 07:39:44PM +0100, Cédric Le Goater wrote:
> The activation of the KVM IRQ device depends on the interrupt mode
> chosen at CAS time by the machine and some methods used at reset or by
> the migration need to be protected.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  hw/intc/spapr_xive_kvm.c | 28 ++++++++++++++++++++++++++++
>  hw/intc/xics_kvm.c       | 25 ++++++++++++++++++++++++-
>  2 files changed, 52 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/intc/spapr_xive_kvm.c b/hw/intc/spapr_xive_kvm.c
> index 93ea8e71047a..d35814c1992e 100644
> --- a/hw/intc/spapr_xive_kvm.c
> +++ b/hw/intc/spapr_xive_kvm.c
> @@ -95,9 +95,15 @@ static void kvmppc_xive_cpu_set_state(XiveTCTX *tctx, Error **errp)
>  
>  void kvmppc_xive_cpu_get_state(XiveTCTX *tctx, Error **errp)
>  {
> +    sPAPRXive *xive = SPAPR_MACHINE(qdev_get_machine())->xive;
>      uint64_t state[4] = { 0 };
>      int ret;
>  
> +    /* The KVM XIVE device is not in use */
> +    if (xive->fd == -1) {
> +        return;
> +    }
> +
>      ret = kvm_get_one_reg(tctx->cs, KVM_REG_PPC_NVT_STATE, state);
>      if (ret != 0) {
>          error_setg_errno(errp, errno,
> @@ -151,6 +157,11 @@ void kvmppc_xive_cpu_connect(XiveTCTX *tctx, Error **errp)
>      unsigned long vcpu_id;
>      int ret;
>  
> +    /* The KVM XIVE device is not in use */
> +    if (xive->fd == -1) {
> +        return;
> +    }
> +
>      /* Check if CPU was hot unplugged and replugged. */
>      if (kvm_cpu_is_enabled(tctx->cs)) {
>          return;
> @@ -234,9 +245,13 @@ static void kvmppc_xive_source_get_state(XiveSource *xsrc)
>  void kvmppc_xive_source_set_irq(void *opaque, int srcno, int val)
>  {
>      XiveSource *xsrc = opaque;
> +    sPAPRXive *xive = SPAPR_XIVE(xsrc->xive);
>      struct kvm_irq_level args;
>      int rc;
>  
> +    /* The KVM XIVE device should be in use */
> +    assert(xive->fd != -1);
> +
>      args.irq = srcno;
>      if (!xive_source_irq_is_lsi(xsrc, srcno)) {
>          if (!val) {
> @@ -580,6 +595,11 @@ int kvmppc_xive_pre_save(sPAPRXive *xive)
>      Error *local_err = NULL;
>      CPUState *cs;
>  
> +    /* The KVM XIVE device is not in use */
> +    if (xive->fd == -1) {
> +        return 0;
> +    }
> +
>      /* Grab the EAT */
>      kvmppc_xive_get_eas_state(xive, &local_err);
>      if (local_err) {
> @@ -612,6 +632,9 @@ int kvmppc_xive_post_load(sPAPRXive *xive, int version_id)
>      Error *local_err = NULL;
>      CPUState *cs;
>  
> +    /* The KVM XIVE device should be in use */
> +    assert(xive->fd != -1);

I'm guessing this is an assert() because the handler shouldn't be
registered when we're not in KVM mode.  But wouldn't that also be true
of the pre_save hook, which errors out rather than asserting?

>      /* Restore the ENDT first. The targetting depends on it. */
>      CPU_FOREACH(cs) {
>          kvmppc_xive_set_eq_state(xive, cs, &local_err);
> @@ -649,6 +672,11 @@ void kvmppc_xive_synchronize_state(sPAPRXive *xive, Error **errp)
>      CPUState *cs;
>      Error *local_err = NULL;
>  
> +    /* The KVM XIVE device is not in use */
> +    if (xive->fd == -1) {
> +        return;
> +    }
> +
>      /*
>       * When the VM is stopped, the sources are masked and the previous
>       * state is saved in anticipation of a migration. We should not
> diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
> index da6a00bc88cc..651bbfdf6966 100644
> --- a/hw/intc/xics_kvm.c
> +++ b/hw/intc/xics_kvm.c
> @@ -68,6 +68,11 @@ static void icp_get_kvm_state(ICPState *icp)
>      uint64_t state;
>      int ret;
>  
> +    /* The KVM XICS device is not in use */
> +    if (kernel_xics_fd == -1) {
> +        return;
> +    }
> +
>      /* ICP for this CPU thread is not in use, exiting */
>      if (!icp->cs) {
>          return;
> @@ -104,6 +109,11 @@ static int icp_set_kvm_state(ICPState *icp, int version_id)
>      uint64_t state;
>      int ret;
>  
> +    /* The KVM XICS device is not in use */
> +    if (kernel_xics_fd == -1) {
> +        return 0;
> +    }
> +
>      /* ICP for this CPU thread is not in use, exiting */
>      if (!icp->cs) {
>          return 0;
> @@ -140,8 +150,8 @@ static void icp_kvm_connect(ICPState *icp, Error **errp)
>      unsigned long vcpu_id;
>      int ret;
>  
> +    /* The KVM XICS device is not in use */
>      if (kernel_xics_fd == -1) {
> -        abort();
>          return;
>      }
>  
> @@ -220,6 +230,11 @@ static void ics_get_kvm_state(ICSState *ics)
>      uint64_t state;
>      int i;
>  
> +    /* The KVM XICS device is not in use */
> +    if (kernel_xics_fd == -1) {
> +        return;
> +    }
> +
>      for (i = 0; i < ics->nr_irqs; i++) {
>          ICSIRQState *irq = &ics->irqs[i];
>  
> @@ -279,6 +294,11 @@ static int ics_set_kvm_state(ICSState *ics, int version_id)
>      int i;
>      Error *local_err = NULL;
>  
> +    /* The KVM XICS device is not in use */
> +    if (kernel_xics_fd == -1) {
> +        return 0;
> +    }
> +
>      for (i = 0; i < ics->nr_irqs; i++) {
>          ICSIRQState *irq = &ics->irqs[i];
>          int ret;
> @@ -325,6 +345,9 @@ void ics_kvm_set_irq(void *opaque, int srcno, int val)
>      struct kvm_irq_level args;
>      int rc;
>  
> +    /* The KVM XICS device should be in use */
> +    assert(kernel_xics_fd != -1);
> +
>      args.irq = srcno + ics->offset;
>      if (ics->irqs[srcno].flags & XICS_FLAGS_IRQ_MSI) {
>          if (!val) {

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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