diff options
author | Alexander Graf <agraf@suse.de> | 2010-02-19 11:00:42 +0100 |
---|---|---|
committer | Avi Kivity <avi@redhat.com> | 2010-04-25 12:35:21 +0300 |
commit | 0564ee8a8611326f28bae2a0455182b458826762 (patch) | |
tree | cef03027a7595370c0ca9bbd13e5446186aa39a1 /arch | |
parent | dba2e123e7502870c965e4b445554bc8e56f78b2 (diff) |
KVM: PPC: Add helpers to modify ppc fields
The PowerPC specification always lists bits from MSB to LSB. That is
really confusing when you're trying to write C code, because it fits
in pretty badly with the normal (1 << xx) schemes.
So I came up with some nice wrappers that allow to get and set fields
in a u64 with bit numbers exactly as given in the spec. That makes the
code in KVM and the spec easier comparable.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/powerpc/include/asm/kvm_ppc.h | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 07612189eb8b..c7fcdd751f14 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -103,6 +103,39 @@ extern void kvmppc_booke_exit(void); extern void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu); +/* + * Cuts out inst bits with ordering according to spec. + * That means the leftmost bit is zero. All given bits are included. + */ +static inline u32 kvmppc_get_field(u64 inst, int msb, int lsb) +{ + u32 r; + u32 mask; + + BUG_ON(msb > lsb); + + mask = (1 << (lsb - msb + 1)) - 1; + r = (inst >> (63 - lsb)) & mask; + + return r; +} + +/* + * Replaces inst bits with ordering according to spec. + */ +static inline u32 kvmppc_set_field(u64 inst, int msb, int lsb, int value) +{ + u32 r; + u32 mask; + + BUG_ON(msb > lsb); + + mask = ((1 << (lsb - msb + 1)) - 1) << (63 - lsb); + r = (inst & ~mask) | ((value << (63 - lsb)) & mask); + + return r; +} + #ifdef CONFIG_PPC_BOOK3S /* We assume we're always acting on the current vcpu */ |