Commit de86eccc authored by Greg Kurz's avatar Greg Kurz Committed by David Gibson
Browse files

xics_kvm: cache already enabled vCPU ids 



Since commit a45863bd ("xics_kvm: Don't enable KVM_CAP_IRQ_XICS if
already enabled"), we were able to re-hotplug a vCPU that had been hot-
unplugged ealier, thanks to a boolean flag in ICPState that we set when
enabling KVM_CAP_IRQ_XICS.

This could work because the lifecycle of all ICPState objects was the
same as the machine. Commit 5bc8d26d ("spapr: allocate the ICPState
object from under sPAPRCPUCore") broke this assumption and now we always
pass a freshly allocated ICPState object (ie, with the flag unset) to
icp_kvm_cpu_setup().

This cause re-hotplug to fail with:

Unable to connect CPU8 to kernel XICS: Device or resource busy

Let's fix this by caching all the vCPU ids for which KVM_CAP_IRQ_XICS was
enabled. This also drops the now useless boolean flag from ICPState.

Reported-by: default avatarLaurent Vivier <lvivier@redhat.com>
Signed-off-by: default avatarGreg Kurz <groug@kaod.org>
Tested-by: default avatarLaurent Vivier <lvivier@redhat.com>
Reviewed-by: default avatarLaurent Vivier <lvivier@redhat.com>
Reviewed-by: default avatarCédric Le Goater <clg@kaod.org>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent 06ec79e8

hw/intc/xics_kvm.c

+20 −7
Original line number Diff line number Diff line
@@ -42,6 +42,14 @@ 


static int kernel_xics_fd = -1;



typedef struct KVMEnabledICP {

    unsigned long vcpu_id;

    QLIST_ENTRY(KVMEnabledICP) node;

} KVMEnabledICP;



static QLIST_HEAD(, KVMEnabledICP)

    kvm_enabled_icps = QLIST_HEAD_INITIALIZER(&kvm_enabled_icps);



/*

 * ICP-KVM

 */
@@ -121,6 +129,8 @@ static void icp_kvm_reset(void *dev) 
static void icp_kvm_cpu_setup(ICPState *icp, PowerPCCPU *cpu)

{

    CPUState *cs = CPU(cpu);

    KVMEnabledICP *enabled_icp;

    unsigned long vcpu_id = kvm_arch_vcpu_id(cs);

    int ret;



    if (kernel_xics_fd == -1) {
@@ -132,18 +142,21 @@ static void icp_kvm_cpu_setup(ICPState *icp, PowerPCCPU *cpu) 
     * which was hot-removed earlier we don't have to renable

     * KVM_CAP_IRQ_XICS capability again.

     */

    if (icp->cap_irq_xics_enabled) {

    QLIST_FOREACH(enabled_icp, &kvm_enabled_icps, node) {

        if (enabled_icp->vcpu_id == vcpu_id) {

            return;

        }

    }



    ret = kvm_vcpu_enable_cap(cs, KVM_CAP_IRQ_XICS, 0, kernel_xics_fd,

                              kvm_arch_vcpu_id(cs));

    ret = kvm_vcpu_enable_cap(cs, KVM_CAP_IRQ_XICS, 0, kernel_xics_fd, vcpu_id);

    if (ret < 0) {

        error_report("Unable to connect CPU%ld to kernel XICS: %s",

                     kvm_arch_vcpu_id(cs), strerror(errno));

        error_report("Unable to connect CPU%ld to kernel XICS: %s", vcpu_id,

                     strerror(errno));

        exit(1);

    }

    icp->cap_irq_xics_enabled = true;

    enabled_icp = g_malloc(sizeof(*enabled_icp));

    enabled_icp->vcpu_id = vcpu_id;

    QLIST_INSERT_HEAD(&kvm_enabled_icps, enabled_icp, node);

}



static void icp_kvm_realize(DeviceState *dev, Error **errp)

include/hw/ppc/xics.h

+0 −1
Original line number Diff line number Diff line
@@ -81,7 +81,6 @@ struct ICPState { 
    uint8_t pending_priority;

    uint8_t mfrr;

    qemu_irq output;

    bool cap_irq_xics_enabled;



    XICSFabric *xics;

};