| Message ID | 1399997646-4716-15-git-send-email-victor.kamensky@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Tue, May 13, 2014 at 09:14:06AM -0700, Victor Kamensky wrote: > Fix isssue with 32bit guests running on top of BE KVM host. Guest > state is retored with double word read operations. Within the high restored (spell check should catch this). "Guest state is restored with double word read operations." I don't know what this sentence is supposed to tell me. > and low word data is already byteswap. This code effectively swaps "data is already byteswap" is not English. data is already byteswapped? > two words within 64bit value. > > Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> > --- > arch/arm64/kvm/sys_regs.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 060c3a9..4438b47 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -51,6 +51,16 @@ static u32 cache_levels; > /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */ > #define CSSELR_MAX 12 > > +/* Word access indexes for 64bit vm accessor */ > +#ifdef CONFIG_CPU_BIG_ENDIAN > +#define CP15_REG_MSW_INDEX 0 > +#define CP15_REG_LSW_INDEX 1 > +#else > +#define CP15_REG_MSW_INDEX 1 > +#define CP15_REG_LSW_INDEX 0 > +#endif > + > + > /* Which cache CCSIDR represents depends on CSSELR value. */ > static u32 get_ccsidr(u32 csselr) > { > @@ -137,9 +147,9 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu, > if (!p->is_aarch32) { > vcpu_sys_reg(vcpu, r->reg) = val; > } else { > - vcpu_cp15(vcpu, r->reg) = val & 0xffffffffUL; > + vcpu_cp15(vcpu, r->reg + CP15_REG_LSW_INDEX) = val & 0xffffffffUL; > if (!p->is_32bit) > - vcpu_cp15(vcpu, r->reg + 1) = val >> 32; > + vcpu_cp15(vcpu, r->reg + CP15_REG_MSW_INDEX) = val >> 32; > } > return true; > } > -- > 1.8.1.4 > I really don't like this. If anything I feel like it should be abstracted inside vcpu_cp15, but wouldn't it be cleaner to do something along the lines of: u64 *regstore = (u64 *)vcpu->arch.ctxt.cp15[r->reg]; if (p->is_32bit) val &= 0xffffffffUL; *regstore = val; But I think the thing that bothers me in general with all these patches is that they deal specially with a lot of situations where the data structure was designed specifically to make the code easy to read, and now it just becomes a really complicated mess. Have you carefully considered other options, redesigning the data structure layout etc.? -Christoffer
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 060c3a9..4438b47 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -51,6 +51,16 @@ static u32 cache_levels; /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */ #define CSSELR_MAX 12 +/* Word access indexes for 64bit vm accessor */ +#ifdef CONFIG_CPU_BIG_ENDIAN +#define CP15_REG_MSW_INDEX 0 +#define CP15_REG_LSW_INDEX 1 +#else +#define CP15_REG_MSW_INDEX 1 +#define CP15_REG_LSW_INDEX 0 +#endif + + /* Which cache CCSIDR represents depends on CSSELR value. */ static u32 get_ccsidr(u32 csselr) { @@ -137,9 +147,9 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu, if (!p->is_aarch32) { vcpu_sys_reg(vcpu, r->reg) = val; } else { - vcpu_cp15(vcpu, r->reg) = val & 0xffffffffUL; + vcpu_cp15(vcpu, r->reg + CP15_REG_LSW_INDEX) = val & 0xffffffffUL; if (!p->is_32bit) - vcpu_cp15(vcpu, r->reg + 1) = val >> 32; + vcpu_cp15(vcpu, r->reg + CP15_REG_MSW_INDEX) = val >> 32; } return true; }
Fix isssue with 32bit guests running on top of BE KVM host. Guest state is retored with double word read operations. Within the high and low word data is already byteswap. This code effectively swaps two words within 64bit value. Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> --- arch/arm64/kvm/sys_regs.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)