| Message ID | 1399997646-4716-12-git-send-email-victor.kamensky@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Tue, May 13, 2014 at 09:14:03AM -0700, Victor Kamensky wrote: > Fix vgic_bitmap_get_reg function to return 'right' word address of > 'unsigned long' bitmap value in case of BE 64bit image. > > Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> > --- > virt/kvm/arm/vgic.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c > index 529c336..d0a1a24 100644 > --- a/virt/kvm/arm/vgic.c > +++ b/virt/kvm/arm/vgic.c > @@ -101,14 +101,34 @@ static u32 vgic_nr_lr; > > static unsigned int vgic_maint_irq; > > +/* > + * struct vgic_bitmap contains union that provides two view of it contains two unions, so: ...contains unions that provide s/two view/two views/ > + * the same data. In one case it is an array of registers of > + * u32 type (.reg), and in the other case it is a bitmape, which is s/bitmape/bitmap/ > + * an array of 'unsgined long' (.reg_ul). It all works well in > + * case of 32-bit (u32 and 'unsigned long' have the same size). "in case of 32-bit" is too vague. Write 'on 32-bit systems' if that's what you mean. > + * It alos works well in 64-bit LE, but breaks on 64-bit BE. s/alos/also/ same with "in 64-bit" as above. > + * In this case word sized register of even index actually resides the word sized register > + * in least significant word of 'unsigned long' which has address in the least significant word of the 'unsigned long' at the register offset plus 4 bytes. > + * at offset plus 4 bytes. And word sized register of odd index the > + * resides at most significant of 'unsigned long' which has offset > + * minus 4 bytes. Define REG_OFFSET_SWIZZLE that would help to > + * change offset of register in case of BE 64bit system. > + */ I actually think this is quite hard to understand, how about: /* * struct vgic_bitmap contains unions that provide two views of * the same data. In one case it is an array of registers of * u32's, and in the other case it is a bitmap of unsigned * longs. * * This does not work on 64-bit BE systems, because the bitmap access * will store two consecutive 32-bit words with the higher-addressed * register's bits at the lower index and the lower-addressed register's * bits at the higher index. * * Therefore, swizzle the register index when accessing the 32-bit word * registers to access the right register's value. */ > +#if defined(CONFIG_CPU_BIG_ENDIAN) && BITS_PER_LONG == 64 > +#define REG_OFFSET_SWIZZLE 1 > +#else > +#define REG_OFFSET_SWIZZLE 0 > +#endif > + > static u32 *vgic_bitmap_get_reg(struct vgic_bitmap *x, > int cpuid, u32 offset) > { > offset >>= 2; > if (!offset) > - return x->percpu[cpuid].reg; > + return x->percpu[cpuid].reg + (offset ^ REG_OFFSET_SWIZZLE); > else > - return x->shared.reg + offset - 1; > + return x->shared.reg + ((offset - 1) ^ REG_OFFSET_SWIZZLE); > } > > static int vgic_bitmap_get_irq_val(struct vgic_bitmap *x, > -- > 1.8.1.4 >
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 529c336..d0a1a24 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -101,14 +101,34 @@ static u32 vgic_nr_lr; static unsigned int vgic_maint_irq; +/* + * struct vgic_bitmap contains union that provides two view of + * the same data. In one case it is an array of registers of + * u32 type (.reg), and in the other case it is a bitmape, which is + * an array of 'unsgined long' (.reg_ul). It all works well in + * case of 32-bit (u32 and 'unsigned long' have the same size). + * It alos works well in 64-bit LE, but breaks on 64-bit BE. + * In this case word sized register of even index actually resides + * in least significant word of 'unsigned long' which has address + * at offset plus 4 bytes. And word sized register of odd index + * resides at most significant of 'unsigned long' which has offset + * minus 4 bytes. Define REG_OFFSET_SWIZZLE that would help to + * change offset of register in case of BE 64bit system. + */ +#if defined(CONFIG_CPU_BIG_ENDIAN) && BITS_PER_LONG == 64 +#define REG_OFFSET_SWIZZLE 1 +#else +#define REG_OFFSET_SWIZZLE 0 +#endif + static u32 *vgic_bitmap_get_reg(struct vgic_bitmap *x, int cpuid, u32 offset) { offset >>= 2; if (!offset) - return x->percpu[cpuid].reg; + return x->percpu[cpuid].reg + (offset ^ REG_OFFSET_SWIZZLE); else - return x->shared.reg + offset - 1; + return x->shared.reg + ((offset - 1) ^ REG_OFFSET_SWIZZLE); } static int vgic_bitmap_get_irq_val(struct vgic_bitmap *x,
Fix vgic_bitmap_get_reg function to return 'right' word address of 'unsigned long' bitmap value in case of BE 64bit image. Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> --- virt/kvm/arm/vgic.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)