Re: [igt-dev] [PATCH i-g-t v2 6/6] tests/xe/mmap: sanity check small-bar

["Souza, Jose" <jose.souza@intel.com>]

On Fri, 2023-07-14 at 09:57 +0100, Matthew Auld wrote:
> On 11/07/2023 17:52, Souza, Jose wrote:
> > On Fri, 2023-06-09 at 16:43 +0100, Matthew Auld wrote:
> > > Some basic sanity checks.
> > > 
> > > Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> > > Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
> > > ---
> > >   lib/xe/xe_ioctl.c  | 28 ++++++++++----
> > >   lib/xe/xe_ioctl.h  |  2 +
> > >   tests/xe/xe_mmap.c | 95 +++++++++++++++++++++++++++++++++++++++++++++-
> > >   3 files changed, 117 insertions(+), 8 deletions(-)
> > > 
> > > diff --git a/lib/xe/xe_ioctl.c b/lib/xe/xe_ioctl.c
> > > index 66a8393fe..6c14f03d1 100644
> > > --- a/lib/xe/xe_ioctl.c
> > > +++ b/lib/xe/xe_ioctl.c
> > > @@ -232,17 +232,31 @@ void xe_vm_destroy(int fd, uint32_t vm)
> > >   	igt_assert_eq(igt_ioctl(fd, DRM_IOCTL_XE_VM_DESTROY, &destroy), 0);
> > >   }
> > >   
> > > +uint32_t __xe_bo_create_flags(int fd, uint32_t vm, uint64_t size, uint32_t flags,
> > > +			      uint32_t *handle)
> > > +{
> > > +	struct drm_xe_gem_create create = {
> > > +		.vm_id = vm,
> > > +		.size = size,
> > > +		.flags = flags,
> > > +	};
> > > +	int err;
> > > +
> > > +	err = igt_ioctl(fd, DRM_IOCTL_XE_GEM_CREATE, &create);
> > > +	if (err)
> > > +		return err;
> > > +
> > > +	*handle = create.handle;
> > > +	return 0;
> > > +}
> > > +
> > >   uint32_t xe_bo_create_flags(int fd, uint32_t vm, uint64_t size, uint32_t flags)
> > >   {
> > > -	struct drm_xe_gem_create create = {
> > > -		.vm_id = vm,
> > > -		.size = size,
> > > -		.flags = flags,
> > > -	};
> > > +	uint32_t handle;
> > >   
> > > -	igt_assert_eq(igt_ioctl(fd, DRM_IOCTL_XE_GEM_CREATE, &create), 0);
> > > +	igt_assert_eq(__xe_bo_create_flags(fd, vm, size, flags, &handle), 0);
> > >   
> > > -	return create.handle;
> > > +	return handle;
> > >   }
> > >   
> > >   uint32_t xe_bo_create(int fd, int gt, uint32_t vm, uint64_t size)
> > > diff --git a/lib/xe/xe_ioctl.h b/lib/xe/xe_ioctl.h
> > > index 049cd183d..85389eff5 100644
> > > --- a/lib/xe/xe_ioctl.h
> > > +++ b/lib/xe/xe_ioctl.h
> > > @@ -64,6 +64,8 @@ void xe_vm_unbind_all_async(int fd, uint32_t vm, uint32_t engine,
> > >   			    uint32_t bo, struct drm_xe_sync *sync,
> > >   			    uint32_t num_syncs);
> > >   void xe_vm_destroy(int fd, uint32_t vm);
> > > +uint32_t __xe_bo_create_flags(int fd, uint32_t vm, uint64_t size, uint32_t flags,
> > > +			      uint32_t *handle);
> > >   uint32_t xe_bo_create_flags(int fd, uint32_t vm, uint64_t size, uint32_t flags);
> > >   uint32_t xe_bo_create(int fd, int gt, uint32_t vm, uint64_t size);
> > >   uint32_t xe_engine_create(int fd, uint32_t vm,
> > > diff --git a/tests/xe/xe_mmap.c b/tests/xe/xe_mmap.c
> > > index 7bfe72e51..b75d8dc5a 100644
> > > --- a/tests/xe/xe_mmap.c
> > > +++ b/tests/xe/xe_mmap.c
> > > @@ -18,14 +18,21 @@
> > >   #include "xe/xe_ioctl.h"
> > >   #include "xe/xe_query.h"
> > >   
> > > +#include <setjmp.h>
> > > +#include <signal.h>
> > >   #include <string.h>
> > >   
> > > -
> > >   /**
> > >    * SUBTEST: system
> > >    * Description: Test mmap on system memory
> > >    */
> > >   
> > > +/**
> > > + * SUBTEST: small-bar
> > > + * Description: Sanity check mmap behaviour on small-bar systems
> > > + * GPU requirements: GPU needs to have dedicated VRAM and using small-bar
> > > + */
> > > +
> > >   /**
> > >    * SUBTEST: %s
> > >    * Description: Test mmap on %arg[1] memory
> > > @@ -111,6 +118,86 @@ static void test_bad_object(int fd)
> > >   	do_ioctl_err(fd, DRM_IOCTL_XE_GEM_MMAP_OFFSET, &mmo, ENOENT);
> > >   }
> > >   
> > > +static jmp_buf jmp;
> > > +
> > > +__noreturn static void sigtrap(int sig)
> > > +{
> > > +	siglongjmp(jmp, sig);
> > > +}
> > > +
> > > +static void trap_sigbus(uint32_t *ptr)
> > > +{
> > > +	sighandler_t old_sigbus;
> > > +
> > > +	old_sigbus = signal(SIGBUS, sigtrap);
> > > +	switch (sigsetjmp(jmp, SIGBUS)) {
> > > +	case SIGBUS:
> > > +		break;
> > > +	case 0:
> > > +		*ptr = 0xdeadbeaf;
> > > +	default:
> > > +		igt_assert(!"reached");
> > > +		break;
> > > +	}
> > > +	signal(SIGBUS, old_sigbus);
> > > +}
> > > +
> > > +/**
> > > + * SUBTEST: small-bar
> > > + * Description: Test mmap behaviour on small-bar systems.
> > > + *
> > > + */
> > > +static void test_small_bar(int fd)
> > > +{
> > > +	uint32_t visible_size = xe_visible_vram_size(fd, 0);
> > > +	uint32_t bo;
> > > +	uint64_t mmo;
> > > +	uint32_t *map;
> > > +
> > > +	/* Some 2BIG invalid cases */
> > > +	igt_assert_neq(__xe_bo_create_flags(fd, 0, visible_size,
> > > +					    visible_vram_memory(fd, 0), &bo),
> > > +		       0);
> > 
> > Are you sure that visible_size will always fail? What about when running it Intel GPU Flex?
> 
> KMD always need some minimal amount of mappable VRAM per tile for 
> driver/hw initialisation, so userspace never really gets the entire 
> thing. I can drop though, the below check should be sufficient.

Okay then

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

> 
> > 
> > Other than that LGTM.
> 
> Thanks.
> 
> > 
> > > +	igt_assert_neq(__xe_bo_create_flags(fd, 0, visible_size + 4096,
> > > +					    visible_vram_memory(fd, 0), &bo),
> > > +		       0);
> > > +
> > > +	/* Normal operation */
> > > +	bo = xe_bo_create_flags(fd, 0, visible_size / 4,
> > > +				visible_vram_memory(fd, 0));
> > > +	mmo = xe_bo_mmap_offset(fd, bo);
> > > +	map = mmap(NULL, 4096, PROT_WRITE, MAP_SHARED, fd, mmo);
> > > +	igt_assert(map != MAP_FAILED);
> > > +
> > > +	map[0] = 0xdeadbeaf;
> > > +
> > > +	munmap(map, 4096);
> > > +	gem_close(fd, bo);
> > > +
> > > +	/* Normal operation with system memory spilling */
> > > +	bo = xe_bo_create_flags(fd, 0, visible_size,
> > > +				visible_vram_memory(fd, 0) |
> > > +				system_memory(fd));
> > > +	mmo = xe_bo_mmap_offset(fd, bo);
> > > +	map = mmap(NULL, 4096, PROT_WRITE, MAP_SHARED, fd, mmo);
> > > +	igt_assert(map != MAP_FAILED);
> > > +
> > > +	map[0] = 0xdeadbeaf;
> > > +
> > > +	munmap(map, 4096);
> > > +	gem_close(fd, bo);
> > > +
> > > +	/* Bogus operation with SIGBUS */
> > > +	bo = xe_bo_create_flags(fd, 0, visible_size + 4096,
> > > +				vram_memory(fd, 0));
> > > +	mmo = xe_bo_mmap_offset(fd, bo);
> > > +	map = mmap(NULL, 4096, PROT_WRITE, MAP_SHARED, fd, mmo);
> > > +	igt_assert(map != MAP_FAILED);
> > > +
> > > +	trap_sigbus(map);
> > > +	gem_close(fd, bo);
> > > +}
> > > +
> > >   igt_main
> > >   {
> > >   	int fd;
> > > @@ -138,6 +225,12 @@ igt_main
> > >   	igt_subtest("bad-object")
> > >   		test_bad_object(fd);
> > >   
> > > +	igt_subtest("small-bar") {
> > > +		igt_require(xe_visible_vram_size(fd, 0));
> > > +		igt_require(xe_visible_vram_size(fd, 0) < xe_vram_size(fd, 0));
> > > +		test_small_bar(fd);
> > > +	}
> > > +
> > >   	igt_fixture {
> > >   		xe_device_put(fd);
> > >   		close(fd);
> >