| Message ID | 20200518113008.15422-2-julien@xen.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Remove the 1GB limitation on Rasberry Pi 4 | expand |
Hi Julien, On Mon, 2020-05-18 at 12:30 +0100, Julien Grall wrote: > From: Julien Grall <jgrall@amazon.com> > > At the moment, Xen is assuming that all the devices are at least 32-bit > DMA capable. However, some SoC have devices that may be able to access > a much restricted range. For instance, the RPI has devices that can > only access the first 1GB of RAM. > > The structure platform_desc is now extended to allow a platform to > override the DMA width. The new is used to implement > arch_get_dma_bit_size(). > > The prototype is now moved in asm-arm/mm.h as the function is not NUMA > specific. The implementation is done in platform.c so we don't have to > include platform.h everywhere. This should be fine as the function is > not expected to be called in hotpath. > > Signed-off-by: Julien Grall <jgrall@amazon.com> Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> > --- > > Cc: Jan Beulich <jbeulich@suse.com> > Cc: Andrew Cooper <andrew.cooper3@citrix.com> > Cc: George Dunlap <george.dunlap@citrix.com> > > I noticed that arch_get_dma_bit_size() is only called when there is more > than one NUMA node. I am a bit unsure what is the reason behind it. > > The goal for Arm is to use arch_get_dma_bit_size() when deciding how low > the first Dom0 bank should be allocated. > --- > xen/arch/arm/platform.c | 5 +++++ > xen/include/asm-arm/mm.h | 2 ++ > xen/include/asm-arm/numa.h | 5 ----- > xen/include/asm-arm/platform.h | 2 ++ > 4 files changed, 9 insertions(+), 5 deletions(-) > > diff --git a/xen/arch/arm/platform.c b/xen/arch/arm/platform.c > index 8eb0b6e57a5a..4db5bbb4c51d 100644 > --- a/xen/arch/arm/platform.c > +++ b/xen/arch/arm/platform.c > @@ -155,6 +155,11 @@ bool platform_device_is_blacklisted(const struct dt_device_node *node) > return (dt_match_node(blacklist, node) != NULL); > } > > +unsigned int arch_get_dma_bitsize(void) > +{ > + return ( platform && platform->dma_bitsize ) ? platform->dma_bitsize : 32; > +} > + > /* > * Local variables: > * mode: C > diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h > index 7df91280bc77..f8ba49b1188f 100644 > --- a/xen/include/asm-arm/mm.h > +++ b/xen/include/asm-arm/mm.h > @@ -366,6 +366,8 @@ int arch_acquire_resource(struct domain *d, unsigned int type, unsigned int id, > return -EOPNOTSUPP; > } > > +unsigned int arch_get_dma_bitsize(void); > + > #endif /* __ARCH_ARM_MM__ */ > /* > * Local variables: > diff --git a/xen/include/asm-arm/numa.h b/xen/include/asm-arm/numa.h > index 490d1f31aa14..31a6de4e2346 100644 > --- a/xen/include/asm-arm/numa.h > +++ b/xen/include/asm-arm/numa.h > @@ -25,11 +25,6 @@ extern mfn_t first_valid_mfn; > #define node_start_pfn(nid) (mfn_x(first_valid_mfn)) > #define __node_distance(a, b) (20) > > -static inline unsigned int arch_get_dma_bitsize(void) > -{ > - return 32; > -} > - > #endif /* __ARCH_ARM_NUMA_H */ > /* > * Local variables: > diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h > index ed4d30a1be7c..997eb2521631 100644 > --- a/xen/include/asm-arm/platform.h > +++ b/xen/include/asm-arm/platform.h > @@ -38,6 +38,8 @@ struct platform_desc { > * List of devices which must not pass-through to a guest > */ > const struct dt_device_match *blacklist_dev; > + /* Override the DMA width (32-bit by default). */ > + unsigned int dma_bitsize; > }; > > /*
On Mon, 18 May 2020, Volodymyr Babchuk wrote: > Hi Julien, > > On Mon, 2020-05-18 at 12:30 +0100, Julien Grall wrote: > > From: Julien Grall <jgrall@amazon.com> > > > > At the moment, Xen is assuming that all the devices are at least 32-bit > > DMA capable. However, some SoC have devices that may be able to access > > a much restricted range. For instance, the RPI has devices that can > > only access the first 1GB of RAM. > > > > The structure platform_desc is now extended to allow a platform to > > override the DMA width. The new is used to implement > > arch_get_dma_bit_size(). > > > > The prototype is now moved in asm-arm/mm.h as the function is not NUMA > > specific. The implementation is done in platform.c so we don't have to > > include platform.h everywhere. This should be fine as the function is > > not expected to be called in hotpath. > > > > Signed-off-by: Julien Grall <jgrall@amazon.com> > Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > > --- > > > > Cc: Jan Beulich <jbeulich@suse.com> > > Cc: Andrew Cooper <andrew.cooper3@citrix.com> > > Cc: George Dunlap <george.dunlap@citrix.com> > > > > I noticed that arch_get_dma_bit_size() is only called when there is more > > than one NUMA node. I am a bit unsure what is the reason behind it. > > > > The goal for Arm is to use arch_get_dma_bit_size() when deciding how low > > the first Dom0 bank should be allocated. > > --- > > xen/arch/arm/platform.c | 5 +++++ > > xen/include/asm-arm/mm.h | 2 ++ > > xen/include/asm-arm/numa.h | 5 ----- > > xen/include/asm-arm/platform.h | 2 ++ > > 4 files changed, 9 insertions(+), 5 deletions(-) > > > > diff --git a/xen/arch/arm/platform.c b/xen/arch/arm/platform.c > > index 8eb0b6e57a5a..4db5bbb4c51d 100644 > > --- a/xen/arch/arm/platform.c > > +++ b/xen/arch/arm/platform.c > > @@ -155,6 +155,11 @@ bool platform_device_is_blacklisted(const struct dt_device_node *node) > > return (dt_match_node(blacklist, node) != NULL); > > } > > > > +unsigned int arch_get_dma_bitsize(void) > > +{ > > + return ( platform && platform->dma_bitsize ) ? platform->dma_bitsize : 32; > > +} > > + > > /* > > * Local variables: > > * mode: C > > diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h > > index 7df91280bc77..f8ba49b1188f 100644 > > --- a/xen/include/asm-arm/mm.h > > +++ b/xen/include/asm-arm/mm.h > > @@ -366,6 +366,8 @@ int arch_acquire_resource(struct domain *d, unsigned int type, unsigned int id, > > return -EOPNOTSUPP; > > } > > > > +unsigned int arch_get_dma_bitsize(void); > > + > > #endif /* __ARCH_ARM_MM__ */ > > /* > > * Local variables: > > diff --git a/xen/include/asm-arm/numa.h b/xen/include/asm-arm/numa.h > > index 490d1f31aa14..31a6de4e2346 100644 > > --- a/xen/include/asm-arm/numa.h > > +++ b/xen/include/asm-arm/numa.h > > @@ -25,11 +25,6 @@ extern mfn_t first_valid_mfn; > > #define node_start_pfn(nid) (mfn_x(first_valid_mfn)) > > #define __node_distance(a, b) (20) > > > > -static inline unsigned int arch_get_dma_bitsize(void) > > -{ > > - return 32; > > -} > > - > > #endif /* __ARCH_ARM_NUMA_H */ > > /* > > * Local variables: > > diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h > > index ed4d30a1be7c..997eb2521631 100644 > > --- a/xen/include/asm-arm/platform.h > > +++ b/xen/include/asm-arm/platform.h > > @@ -38,6 +38,8 @@ struct platform_desc { > > * List of devices which must not pass-through to a guest > > */ > > const struct dt_device_match *blacklist_dev; > > + /* Override the DMA width (32-bit by default). */ > > + unsigned int dma_bitsize; > > }; > > > > /* >
diff --git a/xen/arch/arm/platform.c b/xen/arch/arm/platform.c index 8eb0b6e57a5a..4db5bbb4c51d 100644 --- a/xen/arch/arm/platform.c +++ b/xen/arch/arm/platform.c @@ -155,6 +155,11 @@ bool platform_device_is_blacklisted(const struct dt_device_node *node) return (dt_match_node(blacklist, node) != NULL); } +unsigned int arch_get_dma_bitsize(void) +{ + return ( platform && platform->dma_bitsize ) ? platform->dma_bitsize : 32; +} + /* * Local variables: * mode: C diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h index 7df91280bc77..f8ba49b1188f 100644 --- a/xen/include/asm-arm/mm.h +++ b/xen/include/asm-arm/mm.h @@ -366,6 +366,8 @@ int arch_acquire_resource(struct domain *d, unsigned int type, unsigned int id, return -EOPNOTSUPP; } +unsigned int arch_get_dma_bitsize(void); + #endif /* __ARCH_ARM_MM__ */ /* * Local variables: diff --git a/xen/include/asm-arm/numa.h b/xen/include/asm-arm/numa.h index 490d1f31aa14..31a6de4e2346 100644 --- a/xen/include/asm-arm/numa.h +++ b/xen/include/asm-arm/numa.h @@ -25,11 +25,6 @@ extern mfn_t first_valid_mfn; #define node_start_pfn(nid) (mfn_x(first_valid_mfn)) #define __node_distance(a, b) (20) -static inline unsigned int arch_get_dma_bitsize(void) -{ - return 32; -} - #endif /* __ARCH_ARM_NUMA_H */ /* * Local variables: diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h index ed4d30a1be7c..997eb2521631 100644 --- a/xen/include/asm-arm/platform.h +++ b/xen/include/asm-arm/platform.h @@ -38,6 +38,8 @@ struct platform_desc { * List of devices which must not pass-through to a guest */ const struct dt_device_match *blacklist_dev; + /* Override the DMA width (32-bit by default). */ + unsigned int dma_bitsize; }; /*