Hi James, > -----Original Message----- > From: James Morse [mailto:james.morse@xxxxxxx] > Sent: 01 March 2017 17:04 > To: Hanjun Guo; Shiju Jose > Cc: christoffer.dall@xxxxxxxxxx; marc.zyngier@xxxxxxx; > pbonzini@xxxxxxxxxx; rkrcmar@xxxxxxxxxx; linux@xxxxxxxxxxxxxxx; > catalin.marinas@xxxxxxx; will.deacon@xxxxxxx; rjw@xxxxxxxxxxxxx; > lenb@xxxxxxxxxx; matt@xxxxxxxxxxxxxxxxxxx; robert.moore@xxxxxxxxx; > lv.zheng@xxxxxxxxx; nkaje@xxxxxxxxxxxxxx; zjzhang@xxxxxxxxxxxxxx; > mark.rutland@xxxxxxx; akpm@xxxxxxxxxxxxxxxxxxxx; > eun.taik.lee@xxxxxxxxxxx; sandeepa.s.prabhu@xxxxxxxxx; > labbott@xxxxxxxxxx; shijie.huang@xxxxxxx; rruigrok@xxxxxxxxxxxxxx; > paul.gortmaker@xxxxxxxxxxxxx; tn@xxxxxxxxxxxx; fu.wei@xxxxxxxxxx; > rostedt@xxxxxxxxxxx; bristot@xxxxxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; kvmarm@xxxxxxxxxxxxxxxxxxxxx; > kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux- > acpi@xxxxxxxxxxxxxxx; linux-efi@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; > Suzuki.Poulose@xxxxxxx; punit.agrawal@xxxxxxx; astone@xxxxxxxxxx; > harba@xxxxxxxxxxxxxx; Tyler Baicar; joe@xxxxxxxxxxx; John Garry; > Gabriele Paoloni; Guohanjun (Hanjun Guo); wangxiongfeng (C); Zhengqiang > (turing) > Subject: Re: [RFC PATCH V1 v4.10-rc3 1/1] acpi: apei: handle GSIV > notification type > > Hi Hanjun, > > On 01/03/17 08:27, Hanjun Guo wrote: > > On 2017/2/28 21:22, James Morse wrote: > >> On 27/02/17 18:19, Shiju Jose wrote: > >>> Add a new GHES error source handling function for GSIV(Global > System > >>> Interrupt Vector). > >>> If an error source's notification type is GSIV, then this handling > >>> function can be registered into the GSIV handler and it can parse > >>> and report error information when they occur. > >> > >> I'm missing some of the story here, but how is GSIV different from > >> 'External Interrupt'? I'm guessing something other than the CPU > takes this 'interrupt'... > > > > Yes, it's the same from CPU side (they are interrupts!), but there is > > history behind them and the usage is different. > > > > I think External Interrupt was introduced before ACPI is available on > > ARM (hardware reduced platforms), so I guess it was used for errors > > reported to OS which were not using SCI mechanism, for example, some > > IO error reporting. > > > > For External Interrupt, we don't use the ACPI event system, so for > the > > firmware, it just report the errors associate with the interrupt > > number, the kernel map the interrupt number and install the irq > > handler for it. > > > > For GSIV based event, it was introduced for hardware reduced platform > > in recent ACPI revision, and ARM64 is one of its consumers. When > > errors are reported via GSIV, ACPI event notification needs to be > > implemented and requires the platform to define a hardware error > > device > > (PNP0C33) in ACPI namespace, and also a generic event device ACPI0013. > > Okay, so for APEI this really means PNP0C33 was Notify()d. 'SCI' means > the same but the route they take to get into APEI is different. > > > > For example, if we are using SPI (ARM GIC) 100 to report errors, > there > > is a ACPI0013 driver in drivers/acpi/evged.c to register the irq, > when > > Aha, this is where the interrupt-magic happens. > > > > error happened and trigger the interrupt, ACPI0013 driver will notify > > the error device (PNP0C33), then error device driver > > (drivers/acpi/hed.c) will process the error data form APEI table... > > > >> The GHES GSIV code below is identical to the behaviour of the SCI > >> Notification type... are these two names for the same thing? (I'm > >> confused!) > > > > SCI is also an 'interrupt' but it's a special irq number for ACPI > > event, and it has GPE (general purpose event) registers behind it, > > which is used only on Intel platforms. SCI based event use > > Method(\_GPE._L0x) to notify the error device (PNP0C33), but GSIV is > > used for HW-reduced platform which has no GPEs. > > > Hope it can clarify something :) > > Yes thanks! (the mist is slowly clearing...) > > If ACPI_HEST_NOTIFY_SCI and ACPI_HEST_NOTIFY_GSIV both mean 'receive > notification from PNP0C33', is there any point having separate lists > and add/remove functions for them? > > Instead, could we rename Linux's ghes_notifier_sci() and ghes_sci list > to describe 'hed' instead, then group the two case statements together? > There would be no need to add a selectable CONFIG_ACPI_APEI_GSIV, as > SCI is already built-in and this way the code added is tiny. The only > thing we would lose is the name 'GSIV' in the not-supported error > message which we don't need if its always supported. This method was tested ok. However we were not sure about reusing/changing the existing ghes_notifier_sci() for gsiv will be accepted. Thus added a separate handling function ghes_notifier_gsiv() for gsiv. Thanks, Shiju > > > Thanks, > > James _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
