From: Daniel Axtens <dja@axtens•net>
To: Nicholas Piggin <npiggin@gmail•com>, kvm-ppc@vger•kernel.org
Cc: linuxppc-dev@lists•ozlabs.org, Nicholas Piggin <npiggin@gmail•com>
Subject: Re: [PATCH v2 09/37] KVM: PPC: Book3S 64: Move hcall early register setup to KVM
Date: Fri, 05 Mar 2021 17:48:07 +1100 [thread overview]
Message-ID: <87im6685aw.fsf@linkitivity.dja.id.au> (raw)
In-Reply-To: <20210225134652.2127648-10-npiggin@gmail.com>
Nicholas Piggin <npiggin@gmail•com> writes:
> System calls / hcalls have a different calling convention than
> other interrupts, so there is code in the KVMTEST to massage these
> into the same form as other interrupt handlers.
>
> Move this work into the KVM hcall handler. This means teaching KVM
> a little more about the low level interrupt handler setup, PACA save
> areas, etc., although that's not obviously worse than the current
> approach of coming up with an entirely different interrupt register
> / save convention.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
> ---
> arch/powerpc/include/asm/exception-64s.h | 13 +++++++
> arch/powerpc/kernel/exceptions-64s.S | 44 ++----------------------
> arch/powerpc/kvm/book3s_64_entry.S | 17 +++++++++
> 3 files changed, 32 insertions(+), 42 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
> index c1a8aac01cf9..bb6f78fcf981 100644
> --- a/arch/powerpc/include/asm/exception-64s.h
> +++ b/arch/powerpc/include/asm/exception-64s.h
> @@ -35,6 +35,19 @@
> /* PACA save area size in u64 units (exgen, exmc, etc) */
> #define EX_SIZE 10
>
> +/* PACA save area offsets */
> +#define EX_R9 0
> +#define EX_R10 8
> +#define EX_R11 16
> +#define EX_R12 24
> +#define EX_R13 32
> +#define EX_DAR 40
> +#define EX_DSISR 48
> +#define EX_CCR 52
> +#define EX_CFAR 56
> +#define EX_PPR 64
> +#define EX_CTR 72
I wonder - now that EX_blah and EX_SIZE both live in the one header
file, if we could calculate EX_SIZE based on the last offset... or have
a BUILD_BUG_ON or something? ... just trying not to lose the sanity
checking afforded to us by the .if macro we lose when moving these out
of exceptions-64s.S...
> +
> /*
> * maximum recursive depth of MCE exceptions
> */
> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
> index 9ae463e8522b..b7092ba87da8 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -21,22 +21,6 @@
> #include <asm/feature-fixups.h>
> #include <asm/kup.h>
>
> -/* PACA save area offsets (exgen, exmc, etc) */
> -#define EX_R9 0
> -#define EX_R10 8
> -#define EX_R11 16
> -#define EX_R12 24
> -#define EX_R13 32
> -#define EX_DAR 40
> -#define EX_DSISR 48
> -#define EX_CCR 52
> -#define EX_CFAR 56
> -#define EX_PPR 64
> -#define EX_CTR 72
> -.if EX_SIZE != 10
> - .error "EX_SIZE is wrong"
> -.endif
> -
> /*
> * Following are fixed section helper macros.
> *
> @@ -1964,45 +1948,21 @@ EXC_VIRT_END(system_call, 0x4c00, 0x100)
>
> #ifdef CONFIG_KVM_BOOK3S_64_HANDLER
> TRAMP_REAL_BEGIN(system_call_kvm)
> - /*
> - * This is a hcall, so register convention is as above, with these
> - * differences:
> - * r13 = PACA
> - * ctr = orig r13
> - * orig r10 saved in PACA
> - */
> - /*
> - * Save the PPR (on systems that support it) before changing to
> - * HMT_MEDIUM. That allows the KVM code to save that value into the
> - * guest state (it is the guest's PPR value).
> - */
> -BEGIN_FTR_SECTION
> - mfspr r10,SPRN_PPR
> - std r10,HSTATE_PPR(r13)
> -END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
> - HMT_MEDIUM
> mfctr r10
> - SET_SCRATCH0(r10)
> - mfcr r10
> - std r12,HSTATE_SCRATCH0(r13)
> - sldi r12,r10,32
> - ori r12,r12,0xc00
> + SET_SCRATCH0(r10) /* Save r13 in SCRATCH0 */
> #ifdef CONFIG_RELOCATABLE
> /*
> - * Requires __LOAD_FAR_HANDLER beause kvmppc_interrupt lives
> + * Requires __LOAD_FAR_HANDLER beause kvmppc_hcall lives
That change probably belongs in the previous patch :)
Beyond that, I'm still wrapping my head around the deep magic going on
here! Hopefully I'll get a bit a bit further next time I look.
Kind regards,
Daniel
> * outside the head section.
> */
> __LOAD_FAR_HANDLER(r10, kvmppc_hcall)
> mtctr r10
> - ld r10,PACA_EXGEN+EX_R10(r13)
> bctr
> #else
> - ld r10,PACA_EXGEN+EX_R10(r13)
> b kvmppc_hcall
> #endif
> #endif
>
> -
> /**
> * Interrupt 0xd00 - Trace Interrupt.
> * This is a synchronous interrupt in response to instruction step or
> diff --git a/arch/powerpc/kvm/book3s_64_entry.S b/arch/powerpc/kvm/book3s_64_entry.S
> index 9572f759255c..1c9518ab7d96 100644
> --- a/arch/powerpc/kvm/book3s_64_entry.S
> +++ b/arch/powerpc/kvm/book3s_64_entry.S
> @@ -13,6 +13,23 @@
> .global kvmppc_hcall
> .balign IFETCH_ALIGN_BYTES
> kvmppc_hcall:
> + /*
> + * This is a hcall, so register convention is as
> + * Documentation/powerpc/papr_hcalls.rst, with these additions:
> + * R13 = PACA
> + * guest R13 saved in SPRN_SCRATCH0
> + * R10 = free
> + */
> +BEGIN_FTR_SECTION
> + mfspr r10,SPRN_PPR
> + std r10,HSTATE_PPR(r13)
> +END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
> + HMT_MEDIUM
> + mfcr r10
> + std r12,HSTATE_SCRATCH0(r13)
> + sldi r12,r10,32
> + ori r12,r12,0xc00
> + ld r10,PACA_EXGEN+EX_R10(r13)
>
> .global kvmppc_interrupt
> .balign IFETCH_ALIGN_BYTES
> --
> 2.23.0
next prev parent reply other threads:[~2021-03-05 6:48 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 13:46 [PATCH v2 00/37] KVM: PPC: Book3S: C-ify the P9 entry/exit code Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 01/37] KVM: PPC: Book3S 64: remove unused kvmppc_h_protect argument Nicholas Piggin
2021-02-26 5:01 ` Daniel Axtens
2021-02-26 23:50 ` Nicholas Piggin
2021-03-05 4:45 ` Daniel Axtens
2021-02-25 13:46 ` [PATCH v2 02/37] KVM: PPC: Book3S HV: Fix CONFIG_SPAPR_TCE_IOMMU=n default hcalls Nicholas Piggin
2021-02-26 5:21 ` Daniel Axtens
2021-02-25 13:46 ` [PATCH v2 03/37] powerpc/64s: Remove KVM handler support from CBE_RAS interrupts Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 04/37] powerpc/64s: remove KVM SKIP test from instruction breakpoint handler Nicholas Piggin
2021-02-26 5:44 ` Daniel Axtens
2021-02-26 23:51 ` Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 05/37] KVM: PPC: Book3S HV: Ensure MSR[ME] is always set in guest MSR Nicholas Piggin
2021-02-26 6:06 ` Daniel Axtens
2021-02-26 23:55 ` Nicholas Piggin
2021-03-05 4:50 ` Daniel Axtens
2021-02-25 13:46 ` [PATCH v2 06/37] KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Nicholas Piggin
2021-03-05 5:03 ` Daniel Axtens
2021-02-25 13:46 ` [PATCH v2 07/37] KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM Nicholas Piggin
2021-03-05 5:54 ` Daniel Axtens
2021-02-25 13:46 ` [PATCH v2 08/37] KVM: PPC: Book3S 64: add hcall interrupt handler Nicholas Piggin
2021-03-05 6:03 ` Daniel Axtens
2021-02-25 13:46 ` [PATCH v2 09/37] KVM: PPC: Book3S 64: Move hcall early register setup to KVM Nicholas Piggin
2021-03-05 6:48 ` Daniel Axtens [this message]
2021-02-25 13:46 ` [PATCH v2 10/37] KVM: PPC: Book3S 64: Move interrupt " Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 11/37] KVM: PPC: Book3S 64: move bad_host_intr check to HV handler Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 12/37] KVM: PPC: Book3S 64: Minimise hcall handler calling convention differences Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 13/37] KVM: PPC: Book3S HV P9: Move radix MMU switching instructions together Nicholas Piggin
2021-02-26 15:56 ` Fabiano Rosas
2021-02-26 23:57 ` Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 14/37] KVM: PPC: Book3S HV P9: implement kvmppc_xive_pull_vcpu in C Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 15/37] KVM: PPC: Book3S HV P9: Move xive vcpu context management into kvmhv_p9_guest_entry Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 16/37] KVM: PPC: Book3S HV P9: Stop handling hcalls in real-mode in the P9 path Nicholas Piggin
2021-02-25 14:51 ` Cédric Le Goater
2021-02-26 23:59 ` Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 17/37] KVM: PPC: Book3S HV P9: Move setting HDEC after switching to guest LPCR Nicholas Piggin
2021-02-26 16:38 ` Fabiano Rosas
2021-02-26 23:59 ` Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 18/37] KVM: PPC: Book3S HV P9: Use large decrementer for HDEC Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 19/37] KVM: PPC: Book3S HV P9: Use host timer accounting to avoid decrementer read Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 20/37] KVM: PPC: Book3S HV P9: Reduce mftb per guest entry/exit Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 21/37] powerpc: add set_dec_or_work API for safely updating decrementer Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 22/37] KVM: PPC: Book3S HV P9: Reduce irq_work vs guest decrementer races Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 23/37] KVM: PPC: Book3S HV P9: Implement the rest of the P9 path in C Nicholas Piggin
2021-02-26 22:37 ` Fabiano Rosas
2021-02-27 0:21 ` Nicholas Piggin
2021-02-27 0:55 ` Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 24/37] KVM: PPC: Book3S HV P9: inline kvmhv_load_hv_regs_and_go into __kvmhv_vcpu_entry_p9 Nicholas Piggin
2021-03-02 13:48 ` Fabiano Rosas
2021-02-25 13:46 ` [PATCH v2 25/37] KVM: PPC: Book3S HV P9: Read machine check registers while MSR[RI] is 0 Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 26/37] KVM: PPC: Book3S HV P9: Improve exit timing accounting coverage Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 27/37] KVM: PPC: Book3S HV P9: Move SPR loading after expiry time check Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 28/37] KVM: PPC: Book3S HV P9: Add helpers for OS SPR handling Nicholas Piggin
2021-03-02 15:04 ` Fabiano Rosas
2021-03-04 11:02 ` Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 29/37] KVM: PPC: Book3S HV P9: Switch to guest MMU context as late as possible Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 30/37] KVM: PPC: Book3S HV: Implement radix prefetch workaround by disabling MMU Nicholas Piggin
2021-03-02 21:21 ` Fabiano Rosas
2021-03-04 11:04 ` Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 31/37] KVM: PPC: Book3S HV: Remove support for dependent threads mode on P9 Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 32/37] KVM: PPC: Book3S HV: Remove radix guest support from P7/8 path Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 33/37] KVM: PPC: Book3S HV: small pseries_do_hcall cleanup Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 34/37] KVM: PPC: Book3S HV: add virtual mode handlers for HPT hcalls and page faults Nicholas Piggin
2021-03-03 20:09 ` Fabiano Rosas
2021-03-04 11:05 ` Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 35/37] KVM: PPC: Book3S HV P9: implement hash guest support Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 36/37] KVM: PPC: Book3S HV P9: implement hash host / " Nicholas Piggin
2021-02-25 13:46 ` [PATCH v2 37/37] KVM: PPC: Book3S HV: remove POWER9 support from P7/8 paths Nicholas Piggin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87im6685aw.fsf@linkitivity.dja.id.au \
--to=dja@axtens$(echo .)net \
--cc=kvm-ppc@vger$(echo .)kernel.org \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=npiggin@gmail$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox