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XEN build configuration should be improved. #9

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aanisov opened this issue Dec 5, 2016 · 0 comments
Open

XEN build configuration should be improved. #9

aanisov opened this issue Dec 5, 2016 · 0 comments

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@aanisov
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aanisov commented Dec 5, 2016

XEN hypervisor and tools build configuration system should be improved following this discussion: https://lists.xenproject.org/archives/html/xen-devel/2016-11/msg02425.html
otyshchenko1 pushed a commit to otyshchenko1/xen that referenced this issue Jan 29, 2021
arm/ioreq: Introduce arch specific bits for IOREQ/DM features
bb28f16 
This patch adds basic IOREQ/DM support on Arm. The subsequent
patches will improve functionality and add remaining bits.

The IOREQ/DM features are supposed to be built with IOREQ_SERVER
option enabled, which is disabled by default on Arm for now.

Please note, the "PIO handling" TODO is expected to left unaddressed
for the current series. It is not an big issue for now while Xen
doesn't have support for vPCI on Arm. On Arm64 they are only used
for PCI IO Bar and we would probably want to expose them to emulator
as PIO access to make a DM completely arch-agnostic. So "PIO handling"
should be implemented when we add support for vPCI.

Signed-off-by: Julien Grall <[email protected]>
Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
[On Arm only]
Tested-by: Wei Chen <[email protected]>

---
Please note, this is a split/cleanup/hardening of Julien's PoC:
"Add support for Guest IO forwarding to a device emulator"

***
I admit, I didn't resolve header dependencies completely.
For now, public/hvm/dm_op.h is included by xen/dm.h, but ought to be included
by arch/arm/dm.c. Details here:
https://lore.kernel.org/xen-devel/[email protected]/
***

Changes RFC -> V1:
   - was split into:
     - arm/ioreq: Introduce arch specific bits for IOREQ/DM features
     - xen/mm: Handle properly reference in set_foreign_p2m_entry() on Arm
   - update patch description
   - update asm-arm/hvm/ioreq.h according to the newly introduced arch functions:
     - arch_hvm_destroy_ioreq_server()
     - arch_handle_hvm_io_completion()
   - update arch files to include xen/ioreq.h
   - remove HVMOP plumbing
   - rewrite a logic to handle properly case when hvm_send_ioreq() returns IO_RETRY
   - add a logic to handle properly handle_hvm_io_completion() return value
   - rename handle_mmio() to ioreq_handle_complete_mmio()
   - move paging_mark_pfn_dirty() to asm-arm/paging.h
   - remove forward declaration for hvm_ioreq_server in asm-arm/paging.h
   - move try_fwd_ioserv() to ioreq.c, provide stubs if !CONFIG_IOREQ_SERVER
   - do not remove #ifdef CONFIG_IOREQ_SERVER in memory.c for guarding xen/ioreq.h
   - use gdprintk in try_fwd_ioserv(), remove unneeded prints
   - update list of #include-s
   - move has_vpci() to asm-arm/domain.h
   - add a comment (TODO) to unimplemented yet handle_pio()
   - remove hvm_mmio_first(last)_byte() and hvm_ioreq_(page/vcpu/server) structs
     from the arch files, they were already moved to the common code
   - remove set_foreign_p2m_entry() changes, they will be properly implemented
     in the follow-up patch
   - select IOREQ_SERVER for Arm instead of Arm64 in Kconfig
   - remove x86's realmode and other unneeded stubs from xen/ioreq.h
   - clafify ioreq_t p.df usage in try_fwd_ioserv()
   - set ioreq_t p.count to 1 in try_fwd_ioserv()

Changes V1 -> V2:
   - was split into:
     - arm/ioreq: Introduce arch specific bits for IOREQ/DM features
     - xen/arm: Stick around in leave_hypervisor_to_guest until I/O has completed
   - update the author of a patch
   - update patch description
   - move a loop in leave_hypervisor_to_guest() to a separate patch
   - set IOREQ_SERVER disabled by default
   - remove already clarified /* XXX */
   - replace BUG() by ASSERT_UNREACHABLE() in handle_pio()
   - remove default case for handling the return value of try_handle_mmio()
   - remove struct hvm_domain, enum hvm_io_completion, struct hvm_vcpu_io,
     struct hvm_vcpu from asm-arm/domain.h, these are common materials now
   - update everything according to the recent changes (IOREQ related function
     names don't contain "hvm" prefixes/infixes anymore, IOREQ related fields
     are part of common struct vcpu/domain now, etc)

Changes V2 -> V3:
   - update patch according the "legacy interface" is x86 specific
   - add dummy arch hooks
   - remove dummy paging_mark_pfn_dirty()
   - don’t include <xen/domain_page.h> in common ioreq.c
   - don’t include <public/hvm/ioreq.h> in arch ioreq.h
   - remove #define ioreq_params(d, i)

Changes V3 -> V4:
   - rebase
   - update patch according to the renaming IO_ -> VIO_ (io_ -> vio_)
     and misc changes to arch hooks
   - update patch according to the IOREQ related dm-op handling changes
   - don't include <xen/ioreq.h> from arch header
   - make all arch hooks out-of-line
   - add a comment above IOREQ_STATUS_* #define-s

Changes V4 -> V5:
   - change the placement of ioreq_server_destroy_all() in arm/domain.c
   - don't include public/hvm/dm_op.h by asm-arm/domain.h
   - include public/hvm/dm_op.h by xen/dm.h
   - put arch ioreq.h directly into asm-arm subdir
   - remove do_dm_op() in arm/dm.c, this is a common material now
   - remove obsolete ioreq_complete_mmio() from asm-arm/ioreq.h
   - optimize arch_ioreq_complete_mmio() to not call try_handle_mmio(),
     but try_handle_mmio(), use ASSERT_UNREACHABLE() if state is incorrect
   - split changes to check_for_vcpu_work() to be squashed with patch xen-troops#15

Changes V5 -> V6:
   - do not include public/hvm/dm_op.h by common dm.h (it was already done
     in patch xen-troops#9)
   - do not use switch(...) for only one case in try_fwd_ioserv()
   - add Stefano's R-b
---
otyshchenko1 pushed a commit to otyshchenko1/xen that referenced this issue Jan 29, 2021
arm/ioreq: Introduce arch specific bits for IOREQ/DM features
95d0fca 
This patch adds basic IOREQ/DM support on Arm. The subsequent
patches will improve functionality and add remaining bits.

The IOREQ/DM features are supposed to be built with IOREQ_SERVER
option enabled, which is disabled by default on Arm for now.

Please note, the "PIO handling" TODO is expected to left unaddressed
for the current series. It is not an big issue for now while Xen
doesn't have support for vPCI on Arm. On Arm64 they are only used
for PCI IO Bar and we would probably want to expose them to emulator
as PIO access to make a DM completely arch-agnostic. So "PIO handling"
should be implemented when we add support for vPCI.

Signed-off-by: Julien Grall <[email protected]>
Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
[On Arm only]
Tested-by: Wei Chen <[email protected]>

---
Please note, this is a split/cleanup/hardening of Julien's PoC:
"Add support for Guest IO forwarding to a device emulator"

***
I admit, I didn't resolve header dependencies completely.
For now, public/hvm/dm_op.h is included by xen/dm.h, but ought to be included
by arch/arm/dm.c. Details here:
https://lore.kernel.org/xen-devel/[email protected]/
***

Changes RFC -> V1:
   - was split into:
     - arm/ioreq: Introduce arch specific bits for IOREQ/DM features
     - xen/mm: Handle properly reference in set_foreign_p2m_entry() on Arm
   - update patch description
   - update asm-arm/hvm/ioreq.h according to the newly introduced arch functions:
     - arch_hvm_destroy_ioreq_server()
     - arch_handle_hvm_io_completion()
   - update arch files to include xen/ioreq.h
   - remove HVMOP plumbing
   - rewrite a logic to handle properly case when hvm_send_ioreq() returns IO_RETRY
   - add a logic to handle properly handle_hvm_io_completion() return value
   - rename handle_mmio() to ioreq_handle_complete_mmio()
   - move paging_mark_pfn_dirty() to asm-arm/paging.h
   - remove forward declaration for hvm_ioreq_server in asm-arm/paging.h
   - move try_fwd_ioserv() to ioreq.c, provide stubs if !CONFIG_IOREQ_SERVER
   - do not remove #ifdef CONFIG_IOREQ_SERVER in memory.c for guarding xen/ioreq.h
   - use gdprintk in try_fwd_ioserv(), remove unneeded prints
   - update list of #include-s
   - move has_vpci() to asm-arm/domain.h
   - add a comment (TODO) to unimplemented yet handle_pio()
   - remove hvm_mmio_first(last)_byte() and hvm_ioreq_(page/vcpu/server) structs
     from the arch files, they were already moved to the common code
   - remove set_foreign_p2m_entry() changes, they will be properly implemented
     in the follow-up patch
   - select IOREQ_SERVER for Arm instead of Arm64 in Kconfig
   - remove x86's realmode and other unneeded stubs from xen/ioreq.h
   - clafify ioreq_t p.df usage in try_fwd_ioserv()
   - set ioreq_t p.count to 1 in try_fwd_ioserv()

Changes V1 -> V2:
   - was split into:
     - arm/ioreq: Introduce arch specific bits for IOREQ/DM features
     - xen/arm: Stick around in leave_hypervisor_to_guest until I/O has completed
   - update the author of a patch
   - update patch description
   - move a loop in leave_hypervisor_to_guest() to a separate patch
   - set IOREQ_SERVER disabled by default
   - remove already clarified /* XXX */
   - replace BUG() by ASSERT_UNREACHABLE() in handle_pio()
   - remove default case for handling the return value of try_handle_mmio()
   - remove struct hvm_domain, enum hvm_io_completion, struct hvm_vcpu_io,
     struct hvm_vcpu from asm-arm/domain.h, these are common materials now
   - update everything according to the recent changes (IOREQ related function
     names don't contain "hvm" prefixes/infixes anymore, IOREQ related fields
     are part of common struct vcpu/domain now, etc)

Changes V2 -> V3:
   - update patch according the "legacy interface" is x86 specific
   - add dummy arch hooks
   - remove dummy paging_mark_pfn_dirty()
   - don’t include <xen/domain_page.h> in common ioreq.c
   - don’t include <public/hvm/ioreq.h> in arch ioreq.h
   - remove #define ioreq_params(d, i)

Changes V3 -> V4:
   - rebase
   - update patch according to the renaming IO_ -> VIO_ (io_ -> vio_)
     and misc changes to arch hooks
   - update patch according to the IOREQ related dm-op handling changes
   - don't include <xen/ioreq.h> from arch header
   - make all arch hooks out-of-line
   - add a comment above IOREQ_STATUS_* #define-s

Changes V4 -> V5:
   - change the placement of ioreq_server_destroy_all() in arm/domain.c
   - don't include public/hvm/dm_op.h by asm-arm/domain.h
   - include public/hvm/dm_op.h by xen/dm.h
   - put arch ioreq.h directly into asm-arm subdir
   - remove do_dm_op() in arm/dm.c, this is a common material now
   - remove obsolete ioreq_complete_mmio() from asm-arm/ioreq.h
   - optimize arch_ioreq_complete_mmio() to not call try_handle_mmio(),
     but try_handle_mmio(), use ASSERT_UNREACHABLE() if state is incorrect
   - split changes to check_for_vcpu_work() to be squashed with patch xen-troops#15

Changes V5 -> V6:
   - do not include public/hvm/dm_op.h by common dm.h (it was already done
     in patch xen-troops#9)
   - do not use switch(...) for only one case in try_fwd_ioserv()
   - add Stefano's R-b
---
andr2000 pushed a commit that referenced this issue Feb 21, 2022
@dfaggioli @jbeulich
tools/libs/light: don't touch nr_vcpus_out if listing vcpus and retur…
d9d3496 
…ning NULL

If we are in libxl_list_vcpu() and we are returning NULL, let's avoid
touching the output parameter *nr_vcpus_out, which the caller should
have initialized to 0.

The current behavior could be problematic if are creating a domain and,
in the meantime, an existing one is destroyed when we have already done
some steps of the loop. At which point, we'd return a NULL list of vcpus
but with something different than 0 as the number of vcpus in that list.
And this can cause troubles in the callers (e.g., nr_vcpus_on_nodes()),
when they do a libxl_vcpuinfo_list_free().

Crashes due to this are rare and difficult to reproduce, but have been
observed, with stack traces looking like this one:

#0  libxl_bitmap_dispose (map=map@entry=0x50) at libxl_utils.c:626
#1  0x00007fe72c993a32 in libxl_vcpuinfo_dispose (p=p@entry=0x38) at _libxl_types.c:692
#2  0x00007fe72c94e3c4 in libxl_vcpuinfo_list_free (list=0x0, nr=<optimized out>) at libxl_utils.c:1059
#3  0x00007fe72c9528bf in nr_vcpus_on_nodes (vcpus_on_node=0x7fe71000eb60, suitable_cpumap=0x7fe721df0d38, tinfo_elements=48, tinfo=0x7fe7101b3900, gc=0x7fe7101bbfa0) at libxl_numa.c:258
#4  libxl__get_numa_candidate (gc=gc@entry=0x7fe7100033a0, min_free_memkb=4233216, min_cpus=4, min_nodes=min_nodes@entry=0, max_nodes=max_nodes@entry=0, suitable_cpumap=suitable_cpumap@entry=0x7fe721df0d38, numa_cmpf=0x7fe72c940110 <numa_cmpf>, cndt_out=0x7fe721df0cf0, cndt_found=0x7fe721df0cb4) at libxl_numa.c:394
#5  0x00007fe72c94152b in numa_place_domain (d_config=0x7fe721df11b0, domid=975, gc=0x7fe7100033a0) at libxl_dom.c:209
#6  libxl__build_pre (gc=gc@entry=0x7fe7100033a0, domid=domid@entry=975, d_config=d_config@entry=0x7fe721df11b0, state=state@entry=0x7fe710077700) at libxl_dom.c:436
#7  0x00007fe72c92c4a5 in libxl__domain_build (gc=0x7fe7100033a0, d_config=d_config@entry=0x7fe721df11b0, domid=975, state=0x7fe710077700) at libxl_create.c:444
#8  0x00007fe72c92de8b in domcreate_bootloader_done (egc=0x7fe721df0f60, bl=0x7fe7100778c0, rc=<optimized out>) at libxl_create.c:1222
#9  0x00007fe72c980425 in libxl__bootloader_run (egc=egc@entry=0x7fe721df0f60, bl=bl@entry=0x7fe7100778c0) at libxl_bootloader.c:403
#10 0x00007fe72c92f281 in initiate_domain_create (egc=egc@entry=0x7fe721df0f60, dcs=dcs@entry=0x7fe7100771b0) at libxl_create.c:1159
#11 0x00007fe72c92f456 in do_domain_create (ctx=ctx@entry=0x7fe71001c840, d_config=d_config@entry=0x7fe721df11b0, domid=domid@entry=0x7fe721df10a8, restore_fd=restore_fd@entry=-1, send_back_fd=send_back_fd@entry=-1, params=params@entry=0x0, ao_how=0x0, aop_console_how=0x7fe721df10f0) at libxl_create.c:1856
#12 0x00007fe72c92f776 in libxl_domain_create_new (ctx=0x7fe71001c840, d_config=d_config@entry=0x7fe721df11b0, domid=domid@entry=0x7fe721df10a8, ao_how=ao_how@entry=0x0, aop_console_how=aop_console_how@entry=0x7fe721df10f0) at libxl_create.c:2075

Signed-off-by: Dario Faggioli <[email protected]>
Tested-by: James Fehlig <[email protected]>
Reviewed-by: Anthony PERARD <[email protected]>
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