[PATCH 7/8] arm64/kexec: Add checks for KVM

[Christoffer Dall]

On Mon, Jan 26, 2015 at 8:19 PM, Mark Rutland <mark.rutland at arm.com> wrote:
> On Sat, Jan 17, 2015 at 12:23:34AM +0000, Geoff Levand wrote:
>> Add runtime checks that fail the arm64 kexec syscall for situations that would
>> result in system instability do to problems in the KVM kernel support.
>> These checks should be removed when the KVM problems are resolved fixed.
>>
>> Signed-off-by: Geoff Levand <geoff at infradead.org>
>> ---
>>  arch/arm64/kernel/machine_kexec.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
>> index 3d84759..a36459d 100644
>> --- a/arch/arm64/kernel/machine_kexec.c
>> +++ b/arch/arm64/kernel/machine_kexec.c
>> @@ -16,6 +16,9 @@
>>  #include <asm/cacheflush.h>
>>  #include <asm/system_misc.h>
>>
>> +/* TODO: Remove this include when KVM can support a kexec reboot. */
>> +#include <asm/virt.h>
>> +
>>  /* Global variables for the relocate_kernel routine. */
>>  extern const unsigned char relocate_new_kernel[];
>>  extern const unsigned long relocate_new_kernel_size;
>> @@ -100,6 +103,13 @@ int machine_kexec_prepare(struct kimage *image)
>>
>>       kexec_image_info(image);
>>
>> +     /* TODO: Remove this message when KVM can support a kexec reboot. */
>> +     if (IS_ENABLED(CONFIG_KVM) && is_hyp_mode_available()) {
>> +             pr_err("%s: Your kernel is configured with KVM support (CONFIG_KVM=y) which currently does not allow for kexec re-boot.\n",
>> +                     __func__);
>> +             return -ENOSYS;
>> +     }
>
> If you really don't want to implement KVM teardown, surely this should
> be at the start of the series, so we don't have a point in the middle
> where things may explode in this case?
>
So this caters to support systems that don't support KVM (don't boot
in EL2) but is configured with both KVM and KEXEC?

Why not just make the kexec config dependent on !KVM ?

-Christoffer