On 23 March 2015 at 17:05, Alex Bennée <alex.bennee@xxxxxxxxxx> wrote:
> The current code was negatively indexing the cpu state array and not
> synchronizing banked spsr register state with the current mode's spsr
> state, causing occasional failures with migration.
>
> Some munging is done to take care of the aarch64 mapping and also to
> ensure the most current value of the spsr is updated to the banked
> registers (relevant for KVM<->TCG migration).
>
> Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
>
> ---
> v2 (ajb)
> - minor tweaks and clarifications
> v3
> - Use the correct bank index function for setting/getting env->spsr
> - only deal with spsrs in elevated exception levels
> v4
> - try and make commentary clearer
> - ensure env->banked_spsr[0] = env->spsr before we sync
> v5
> - fix banking index now banking fixed
> - keep wide spacing on [ ] forms
> - claimed authorship
>
> diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c
> index 857e970..5270fa7 100644
> --- a/target-arm/kvm64.c
> +++ b/target-arm/kvm64.c
> @@ -139,6 +139,7 @@ int kvm_arch_put_registers(CPUState *cs, int level)
> uint64_t val;
> int i;
> int ret;
> + unsigned int el;
>
> ARMCPU *cpu = ARM_CPU(cs);
> CPUARMState *env = &cpu->env;
> @@ -205,9 +206,24 @@ int kvm_arch_put_registers(CPUState *cs, int level)
> return ret;
> }
>
> + /* Saved Program State Registers
> + *
> + * Before we restore from the banked_spsr[] array we need to
> + * ensure that any modifications to env->spsr are correctly
> + * reflected in the banks.
> + */
> + el = arm_current_el(env);
> + if (el > 0) {
> + i = is_a64(env) ?
> + aarch64_banked_spsr_index(el) :
> + bank_number(env->uncached_cpsr & CPSR_M);
> + env->banked_spsr[i] = env->spsr;
This doesn't look right. If we're currently A64 then
env->spsr is unused and this code will trash one of
the banked_spsr[] fields.
> + }
> +
> + /* KVM 0-4 map to QEMU banks 1-5 */
> for (i = 0; i < KVM_NR_SPSR; i++) {
> reg.id = AARCH64_CORE_REG(spsr[i]);
> - reg.addr = (uintptr_t) &env->banked_spsr[i - 1];
> + reg.addr = (uintptr_t) &env->banked_spsr[i + 1];
> ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, ®);
> if (ret) {
> return ret;
> @@ -253,11 +269,13 @@ int kvm_arch_put_registers(CPUState *cs, int level)
> return ret;
> }
>
> +
Stray extra space.
-- PMM
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