| Message ID | 20170912025307.45376-1-aik@ozlabs.ru |
|---|---|
| State | New |
| Headers | show |
| Series | [qemu] vfio, spapr: Fix levels calculation | expand |
On Tue, Sep 12, 2017 at 12:53:07PM +1000, Alexey Kardashevskiy wrote: > The existing tries to round up the number of pages but @pages is always > calculated as the rounded up value minus one which makes ctz64() always > return 0 and have create.levels always set 1. > > This removes wrong "-1" and allows having more than 1 levels. This becomes > handy for >128GB guests with standard 64K pages as this requires blocks > with zone order 9 and the popular limit of CONFIG_FORCE_MAX_ZONEORDER=9 > means that only blocks up to order 8 are allowed. > > Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Applied to ppc-for-2.11. > --- > hw/vfio/spapr.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/vfio/spapr.c b/hw/vfio/spapr.c > index 32fd6a9b54..259397c002 100644 > --- a/hw/vfio/spapr.c > +++ b/hw/vfio/spapr.c > @@ -163,7 +163,7 @@ int vfio_spapr_create_window(VFIOContainer *container, > */ > entries = create.window_size >> create.page_shift; > pages = MAX((entries * sizeof(uint64_t)) / getpagesize(), 1); > - pages = MAX(pow2ceil(pages) - 1, 1); /* Round up */ > + pages = MAX(pow2ceil(pages), 1); /* Round up */ > create.levels = ctz64(pages) / 6 + 1; > > ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
diff --git a/hw/vfio/spapr.c b/hw/vfio/spapr.c index 32fd6a9b54..259397c002 100644 --- a/hw/vfio/spapr.c +++ b/hw/vfio/spapr.c @@ -163,7 +163,7 @@ int vfio_spapr_create_window(VFIOContainer *container, */ entries = create.window_size >> create.page_shift; pages = MAX((entries * sizeof(uint64_t)) / getpagesize(), 1); - pages = MAX(pow2ceil(pages) - 1, 1); /* Round up */ + pages = MAX(pow2ceil(pages), 1); /* Round up */ create.levels = ctz64(pages) / 6 + 1; ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
The existing tries to round up the number of pages but @pages is always calculated as the rounded up value minus one which makes ctz64() always return 0 and have create.levels always set 1. This removes wrong "-1" and allows having more than 1 levels. This becomes handy for >128GB guests with standard 64K pages as this requires blocks with zone order 9 and the popular limit of CONFIG_FORCE_MAX_ZONEORDER=9 means that only blocks up to order 8 are allowed. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> --- hw/vfio/spapr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)