Re: [PATCH v4 06/10] arm_mpam: propagate MSC access errors for state saving function
Sudeep Holla <[email protected]>
| Newsgroups | org.kernel.vger.linux-acpi,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <20260724-important-curassow-of-support-ce4777@sudeepholla> |
On Thu, Jul 23, 2026 at 05:54:50PM +0200, Andre Przywara wrote: > Allow the mpam_save_mbwu_state() function to return an error, and > propagate read and write errors from the lower level up. > > Signed-off-by: Andre Przywara <[email protected]> > --- > drivers/resctrl/mpam_devices.c | 29 ++++++++++++++++++++++------- > 1 file changed, 22 insertions(+), 7 deletions(-) > > diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c > index bcff53477133..6329443c451f 100644 > --- a/drivers/resctrl/mpam_devices.c > +++ b/drivers/resctrl/mpam_devices.c > @@ -1833,22 +1833,37 @@ static int mpam_save_mbwu_state(void *arg) > > mon_sel = FIELD_PREP(MSMON_CFG_MON_SEL_MON_SEL, i) | > FIELD_PREP(MSMON_CFG_MON_SEL_RIS, ris->ris_idx); > - mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel); > - mpam_read_monsel_reg(msc, CFG_MBWU_FLT, &cur_flt); > - mpam_read_monsel_reg(msc, CFG_MBWU_CTL, &cur_ctl); > - mpam_write_monsel_reg(msc, CFG_MBWU_CTL, 0); > + ret = mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel); > + if (ret) > + return ret; > + ret = mpam_read_monsel_reg(msc, CFG_MBWU_FLT, &cur_flt); > + if (ret) > + return ret; > + ret = mpam_read_monsel_reg(msc, CFG_MBWU_CTL, &cur_ctl); > + if (ret) > + return ret; How does it work in general with PCC. Now that you can fail at any point, what happens to the write that occurs before a failed read like above one. Who will take care of erasing those new writes or it doesn't matter ? Just checking as I don't have much knowledge on MPAM intrinsics. -- Regards, Sudeep