On 17.01.18 08:57, Heiko Carstens wrote:
On Tue, Jan 16, 2018 at 09:25:12PM +0100, David Hildenbrand wrote:+struct kvm_s390_gisa { + u32 next_alert; + u8 ipm; + u8 reserved01; + u8:6; + u8 g:1; + u8 c:1; + u8 iam; + u8 reserved02[4]; + u32 airq_count; +}; + /* - * sie_page2 has to be allocated as DMA because fac_list and crycb need - * 31bit addresses in the sie control block. + * sie_page2 has to be allocated as DMA because fac_list, crycb and + * gisa need 31bit addresses in the sie control block. */ struct sie_page2 { __u64 fac_list[S390_ARCH_FAC_LIST_SIZE_U64]; /* 0x0000 */ struct kvm_s390_crypto_cb crycb; /* 0x0800 */ - u8 reserved900[0x1000 - 0x900]; /* 0x0900 */ + struct kvm_s390_gisa gisa __aligned(sizeof(struct kvm_s390_gisa)); /* 0x0900 */can we instead specify sie_page2 as packed if really needed? (I can see that we have a BUILD_BUG_ON below, which is nice) (alignment within well defined data structures looks strange)
I'm doing that because the gisa requires "integral boundary" alignment that changes with a later patch when I introduce format-1.
The alignment, if needed, should go to the definition of struct kvm_s390_gisa above. The structure needs at least an alignment of eight bytes since bitops are used to modify ipm (in a later patch), by using a (long *) cast to this structure.
adding this to the definition does not allow to use sizeof() for the currently defined struct. Thus I would have to explicitly specify the
size... :(
But of course it is all naturally aligned anyway... ;)
Thanks Michael
