On Tue, 4 Sep 2018 17:15:49 +0800
Yi Min Zhao <zyi...@linux.ibm.com> wrote:
> Common function measurement block is used to report counters of
> successfully issued pcilg/stg/stb and rpcit instructions. This patch
> introduces a new struct ZpciFmb and schedules a timer callback to
> copy fmb to the guest memory at a interval time which is set to
> 4s by default. While attemping to update fmb failed, an event error
> would be generated. After pcilg/stg/stb and rpcit interception
> handlers issue successfully, increase the related counter. The guest
> could pass null address to switch off FMB and stop corresponding
> timer.
Hard to review without documentation, but some comments below.
>
> Signed-off-by: Yi Min Zhao <zyi...@linux.ibm.com>
> Reviewed-by: Pierre Morel<pmo...@linux.ibm.com>
> ---
> hw/s390x/s390-pci-bus.c | 3 +-
> hw/s390x/s390-pci-bus.h | 24 +++++++++++
> hw/s390x/s390-pci-inst.c | 105
> +++++++++++++++++++++++++++++++++++++++++++++--
> hw/s390x/s390-pci-inst.h | 1 +
> 4 files changed, 129 insertions(+), 4 deletions(-)
(...)
> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
> index 7b61367ee3..1ed5cb91d0 100644
> --- a/hw/s390x/s390-pci-inst.c
> +++ b/hw/s390x/s390-pci-inst.c
> @@ -456,6 +457,10 @@ int pcilg_service_call(S390CPU *cpu, uint8_t r1, uint8_t
> r2, uintptr_t ra)
> return 0;
> }
>
> + if (pbdev->fmb_addr) {
> + pbdev->fmb.ld_ops++;
> + }
As fmb is a part of the structure, just update it unconditionally?
You'll only copy it to the guest if measurements are active anyway.
> +
> env->regs[r1] = data;
> setcc(cpu, ZPCI_PCI_LS_OK);
> return 0;
(...)
> @@ -889,6 +905,63 @@ void pci_dereg_ioat(S390PCIIOMMU *iommu)
> iommu->g_iota = 0;
> }
>
> +void fmb_timer_free(S390PCIBusDevice *pbdev)
> +{
> + if (pbdev->fmb_timer) {
> + timer_del(pbdev->fmb_timer);
> + timer_free(pbdev->fmb_timer);
> + pbdev->fmb_timer = NULL;
> + }
> + pbdev->fmb_addr = 0;
> + memset(&pbdev->fmb, 0, sizeof(ZpciFmb));
Maybe move clearing the buffer to before you enable measurements
instead? (Needed to make my suggestion above work correctly.)
> +}
> +
> +static int fmb_do_update(S390PCIBusDevice *pbdev, uint8_t offset, int len)
> +{
> + MemTxResult ret;
> +
> + ret = address_space_write(&address_space_memory,
> + pbdev->fmb_addr + (uint64_t)offset,
> + MEMTXATTRS_UNSPECIFIED,
> + (uint8_t *)&pbdev->fmb + offset,
> + len);
> + if (ret) {
> + s390_pci_generate_error_event(ERR_EVENT_FMBA, pbdev->fh, pbdev->fid,
> + pbdev->fmb_addr, 0);
> + fmb_timer_free(pbdev);
So, failure to update the guest-provided area is supposed to disable
measurements?
> + }
> +
> + return ret;
> +}
> +
> +static void fmb_update(void *opaque)
> +{
> + S390PCIBusDevice *pbdev = opaque;
> + int64_t t = qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL);
> + uint8_t offset = offsetof(ZpciFmb, last_update);
> +
> + /* Update U bit */
> + pbdev->fmb.last_update |= UPDATE_U_BIT;
> + if (fmb_do_update(pbdev, offset, sizeof(uint64_t))) {
> + return;
> + }
> +
> + /* Update FMB counters */
> + pbdev->fmb.sample++;
> + if (fmb_do_update(pbdev, 0, sizeof(ZpciFmb))) {
> + return;
> + }
> +
> + /* Clear U bit and update the time */
> + pbdev->fmb.last_update = time2tod(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
> + pbdev->fmb.last_update &= ~UPDATE_U_BIT;
> + if (fmb_do_update(pbdev, offset, sizeof(uint64_t))) {
> + return;
> + }
> +
> + timer_mod(pbdev->fmb_timer, t + DEFAULT_MUI);
> +}
> +
> int mpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar,
> uintptr_t ra)
> {
> @@ -1018,9 +1091,35 @@ int mpcifc_service_call(S390CPU *cpu, uint8_t r1,
> uint64_t fiba, uint8_t ar,
> s390_set_status_code(env, r1, ZPCI_MOD_ST_SEQUENCE);
> }
> break;
> - case ZPCI_MOD_FC_SET_MEASURE:
> - pbdev->fmb_addr = ldq_p(&fib.fmb_addr);
> + case ZPCI_MOD_FC_SET_MEASURE: {
> + uint64_t fmb_addr = ldq_p(&fib.fmb_addr);
> +
> + if (fmb_addr & FMBK_MASK) {
> + cc = ZPCI_PCI_LS_ERR;
> + s390_pci_generate_error_event(ERR_EVENT_FMBPRO, pbdev->fh,
> + pbdev->fid, fmb_addr, 0);
> + fmb_timer_free(pbdev);
> + break;
> + }
> +
> + if (!fmb_addr) {
> + /* Stop updating FMB. */
> + fmb_timer_free(pbdev);
> + break;
> + }
> +
> + pbdev->fmb_addr = fmb_addr;
> + if (!pbdev->fmb_timer) {
> + pbdev->fmb_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
> + fmb_update, pbdev);
> + } else if (timer_pending(pbdev->fmb_timer)) {
> + /* Remove pending timer to update FMB address. */
> + timer_del(pbdev->fmb_timer);
> + }
So, setting fmb_addr to another address will not reset the counters,
but just cause the blocks to be stored into a different address?
> + timer_mod(pbdev->fmb_timer,
> + qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + DEFAULT_MUI);
> break;
> + }
> default:
> s390_program_interrupt(&cpu->env, PGM_OPERAND, 6, ra);
> cc = ZPCI_PCI_LS_ERR;
