* Re: target/ppc: sPAPR invalid function calls when compiling without TCG
@ 2021-04-20 18:27 Lucas Mateus Martins Araujo e Castro
2021-04-21 4:06 ` David Gibson
0 siblings, 1 reply; 6+ messages in thread
From: Lucas Mateus Martins Araujo e Castro @ 2021-04-20 18:27 UTC (permalink / raw)
To: David Gibson; +Cc: Bruno Piazera Larsen, qemu-ppc, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 1365 bytes --]
________________________________
>> spapr_hcall.c:
>> function h_enter call ppc_hash64_hpte_page_shift_noslb, ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
>> function remove_hpte call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
>> function h_protect call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
>> function h_read call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
>> function rehash_hpte call ppc_hash64_hpte_page_shift_noslb
>> function rehash_hpt call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
>
>h_enter, remove_hpte, h_protect, h_read and rehash_hpte should never
>be called for a KVM guest (KVM will intercept the relevant hcalls
>before they reach qemu). I think it would make sense to split of a
>TCG only portion of spapr_hcall.c into a new file. You'll then
>probably need !TCG stubs for those hypercalls, which should trip a
>fatal error (if KVM hasn't handled the calls, there's nothing we can
>do that will salvage the situation).
Besides the aforementioned functions, will all spapr hypercalls beginning with H_* be intercepted
(and therefore, should trip a fatal error in the KVM-only file) or only a subset of these functions will
be intercepted? If the latter is there an interval of opcodes that'll be intercepted?
[-- Attachment #2: Type: text/html, Size: 2358 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: target/ppc: sPAPR invalid function calls when compiling without TCG
2021-04-20 18:27 target/ppc: sPAPR invalid function calls when compiling without TCG Lucas Mateus Martins Araujo e Castro
@ 2021-04-21 4:06 ` David Gibson
0 siblings, 0 replies; 6+ messages in thread
From: David Gibson @ 2021-04-21 4:06 UTC (permalink / raw)
To: Lucas Mateus Martins Araujo e Castro
Cc: Bruno Piazera Larsen, qemu-ppc, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 2548 bytes --]
On Tue, Apr 20, 2021 at 06:27:38PM +0000, Lucas Mateus Martins Araujo e Castro wrote:
>
>
>
> ________________________________
>
> >> spapr_hcall.c:
> >> function h_enter call ppc_hash64_hpte_page_shift_noslb, ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
> >> function remove_hpte call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
> >> function h_protect call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
> >> function h_read call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
> >> function rehash_hpte call ppc_hash64_hpte_page_shift_noslb
> >> function rehash_hpt call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
> >
> >h_enter, remove_hpte, h_protect, h_read and rehash_hpte should never
> >be called for a KVM guest (KVM will intercept the relevant hcalls
> >before they reach qemu). I think it would make sense to split of a
> >TCG only portion of spapr_hcall.c into a new file. You'll then
> >probably need !TCG stubs for those hypercalls, which should trip a
> >fatal error (if KVM hasn't handled the calls, there's nothing we can
> >do that will salvage the situation).
>
> Besides the aforementioned functions, will all spapr hypercalls
> beginning with H_* be intercepted (and therefore, should trip a
> fatal error in the KVM-only file) or only a subset of these
> functions will be intercepted?
No, only a few hcalls will be KVM intercepted. There are basically
two categories:
1) hcalls which *must* be implemented in KVM, because qemu doesn't
have access to the KVM data structures to implement them. I
think this is pretty much just the MMU related hypercalls.
2) performance critical hcalls where we have a KVM accelerated
implementation, but *could* be implemented in qemu (and in a few
cases the kernel fast path will fall back to the qemu slow path
sometimes)
> If the latter is there an interval of
> opcodes that'll be intercepted?
No. The opcode numbers aren't defined by KVM or qemu, they're from
from PAPR/PowerVM and have no bearing on how concerns are divided in
the KVM/qemu world. I'd start by only separating hypercall
implementations which are actively causing you problems (calling into
TCG code is a strong hint that its in category (1)).
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: target/ppc: sPAPR invalid function calls when compiling without TCG
@ 2021-04-19 19:04 Lucas Mateus Martins Araujo e Castro
2021-04-20 0:09 ` David Gibson
0 siblings, 1 reply; 6+ messages in thread
From: Lucas Mateus Martins Araujo e Castro @ 2021-04-19 19:04 UTC (permalink / raw)
To: David Gibson; +Cc: Bruno Piazera Larsen, qemu-ppc, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 1320 bytes --]
>> spapr_hcall.c:
>> function h_enter call ppc_hash64_hpte_page_shift_noslb, ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
>> function remove_hpte call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
>> function h_protect call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
>> function h_read call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
>> function rehash_hpte call ppc_hash64_hpte_page_shift_noslb
>> function rehash_hpt call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
>h_enter, remove_hpte, h_protect, h_read and rehash_hpte should never
>be called for a KVM guest (KVM will intercept the relevant hcalls
>before they reach qemu). I think it would make sense to split of a
>TCG only portion of spapr_hcall.c into a new file. You'll then
>probably need !TCG stubs for those hypercalls, which should trip a
>fatal error (if KVM hasn't handled the calls, there's nothing we can
>do that will salvage the situation).
These functions are static, so I thought about turning them into non-static functions and creating the prototype in
internal.h and changing hw/ppc/meson.build to add the correct .c file but hw/ppc/ doesn't have an internal.h
What is the best way to handle this static functions?
[-- Attachment #2: Type: text/html, Size: 2258 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: target/ppc: sPAPR invalid function calls when compiling without TCG
2021-04-19 19:04 Lucas Mateus Martins Araujo e Castro
@ 2021-04-20 0:09 ` David Gibson
0 siblings, 0 replies; 6+ messages in thread
From: David Gibson @ 2021-04-20 0:09 UTC (permalink / raw)
To: Lucas Mateus Martins Araujo e Castro
Cc: Bruno Piazera Larsen, qemu-ppc, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 1890 bytes --]
On Mon, Apr 19, 2021 at 07:04:34PM +0000, Lucas Mateus Martins Araujo e Castro wrote:
>
>
> >> spapr_hcall.c:
> >> function h_enter call ppc_hash64_hpte_page_shift_noslb, ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
> >> function remove_hpte call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
> >> function h_protect call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
> >> function h_read call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
> >> function rehash_hpte call ppc_hash64_hpte_page_shift_noslb
> >> function rehash_hpt call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
>
> >h_enter, remove_hpte, h_protect, h_read and rehash_hpte should never
> >be called for a KVM guest (KVM will intercept the relevant hcalls
> >before they reach qemu). I think it would make sense to split of a
> >TCG only portion of spapr_hcall.c into a new file. You'll then
> >probably need !TCG stubs for those hypercalls, which should trip a
> >fatal error (if KVM hasn't handled the calls, there's nothing we can
> >do that will salvage the situation).
>
> These functions are static, so I thought about turning them into non-static functions and creating the prototype in
> internal.h and changing hw/ppc/meson.build to add the correct .c file but hw/ppc/ doesn't have an internal.h
>
> What is the best way to handle this static functions?
They're static because their only direct use is passing to
spapr_register_hypercall() in hypercall_register_types(). You can put
your own register types function in the new KVM-only file, with those
calls, so everything will stay static.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* target/ppc: sPAPR invalid function calls when compiling without TCG
@ 2021-04-14 18:28 Lucas Mateus Martins Araujo e Castro
2021-04-19 5:17 ` David Gibson
0 siblings, 1 reply; 6+ messages in thread
From: Lucas Mateus Martins Araujo e Castro @ 2021-04-14 18:28 UTC (permalink / raw)
To: qemu-ppc, qemu-devel; +Cc: Bruno Piazera Larsen, David Gibson
[-- Attachment #1: Type: text/plain, Size: 1833 bytes --]
Hi, I have been working on billionai's patch to enable the --disable-tcg option on PowerPC and one of the problems is that 5 files in hw/ppc use functions implemented in mmu-hash64.c which is not compiled with --disable-tcg, I'd like to know how to correct the spapr function call, should I
* change the calls to generic functions that should call the correct function based on if kvm is being used or not,
* should I just implement said functions independently of mmu-hash64.c and always call them,
* should I just implement said functions independently of mmu-hash64.c and only call it with --disable-tcg option turned on,
* find a way to not have said calls when compiling without TCG as they're not necessary,
* just create a stub
Here's when each function is called by each .c:
spapr.c:
function do_lpcr_sync call ppc_store_lpcr
spapr_hcall.c:
function h_enter call ppc_hash64_hpte_page_shift_noslb, ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
function remove_hpte call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
function h_protect call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
function h_read call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
function rehash_hpte call ppc_hash64_hpte_page_shift_noslb
function rehash_hpt call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
spapr_rtas.c:
function rtas_start_cpu call ppc_store_lpcr
function rtas_stop_self call ppc_store_lpcr
spapr_spapr_cpu_core.c
function spapr_reset_vcpu call ppc_store_lpcr
function spapr_cpu_set_entry_state call ppc_store_lpcr
spapr_caps.c:
function cap_large_decr_cpu_apply call ppc_store_lpcr
function cap_hpt_maxpagesize_cpu_apply call ppc_hash64_filter_pagesizes
[-- Attachment #2: Type: text/html, Size: 4787 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: target/ppc: sPAPR invalid function calls when compiling without TCG
2021-04-14 18:28 Lucas Mateus Martins Araujo e Castro
@ 2021-04-19 5:17 ` David Gibson
0 siblings, 0 replies; 6+ messages in thread
From: David Gibson @ 2021-04-19 5:17 UTC (permalink / raw)
To: Lucas Mateus Martins Araujo e Castro
Cc: Bruno Piazera Larsen, qemu-ppc, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 2939 bytes --]
On Wed, Apr 14, 2021 at 06:28:26PM +0000, Lucas Mateus Martins Araujo e Castro wrote:
> Hi, I have been working on billionai's patch to enable the --disable-tcg option on PowerPC and one of the problems is that 5 files in hw/ppc use functions implemented in mmu-hash64.c which is not compiled with --disable-tcg, I'd like to know how to correct the spapr function call, should I
>
> * change the calls to generic functions that should call the correct function based on if kvm is being used or not,
> * should I just implement said functions independently of mmu-hash64.c and always call them,
> * should I just implement said functions independently of mmu-hash64.c and only call it with --disable-tcg option turned on,
> * find a way to not have said calls when compiling without TCG as they're not necessary,
> * just create a stub
>
> Here's when each function is called by each .c:
> spapr.c:
> function do_lpcr_sync call ppc_store_lpcr
I think ppc_store_lpcr() needs to be moved so that it's compiled with
KVM as well, but #ifdef out the hreg_compute_hflags() line in that case.
>
> spapr_hcall.c:
> function h_enter call ppc_hash64_hpte_page_shift_noslb, ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
> function remove_hpte call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
> function h_protect call ppc_hash64_map_hptes, ppc_hash64_unmap_hptes and ppc_hash64_tlb_flush_hpte
> function h_read call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
> function rehash_hpte call ppc_hash64_hpte_page_shift_noslb
> function rehash_hpt call ppc_hash64_map_hptes and ppc_hash64_unmap_hptes
h_enter, remove_hpte, h_protect, h_read and rehash_hpte should never
be called for a KVM guest (KVM will intercept the relevant hcalls
before they reach qemu). I think it would make sense to split of a
TCG only portion of spapr_hcall.c into a new file. You'll then
probably need !TCG stubs for those hypercalls, which should trip a
fatal error (if KVM hasn't handled the calls, there's nothing we can
do that will salvage the situation).
> spapr_rtas.c:
> function rtas_start_cpu call ppc_store_lpcr
> function rtas_stop_self call ppc_store_lpcr
As above.
> spapr_spapr_cpu_core.c
> function spapr_reset_vcpu call ppc_store_lpcr
> function spapr_cpu_set_entry_state call ppc_store_lpcr
As above.
> spapr_caps.c:
> function cap_large_decr_cpu_apply call ppc_store_lpcr
As above.
> function cap_hpt_maxpagesize_cpu_apply call ppc_hash64_filter_pagesizes
Ok, you definitely need the filter_pagesizes logic, even with KVM, so
that will also have to be moved out of the TCG only file.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-04-21 4:08 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-20 18:27 target/ppc: sPAPR invalid function calls when compiling without TCG Lucas Mateus Martins Araujo e Castro
2021-04-21 4:06 ` David Gibson
-- strict thread matches above, loose matches on Subject: below --
2021-04-19 19:04 Lucas Mateus Martins Araujo e Castro
2021-04-20 0:09 ` David Gibson
2021-04-14 18:28 Lucas Mateus Martins Araujo e Castro
2021-04-19 5:17 ` David Gibson
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).