Gregory Haskins wrote:
> Newer userspace may run on an older kernel. Therefore we need a way to
> check the capabilities of the kernel so that we can downgrade userspace
> dynamically if necessary
>
> Signed-off-by: Gregory Haskins <[EMAIL PROTECTED]>
> ---
>
> qemu/qemu-kvm.c | 19 +++++++++++++++++++
> user/kvmctl.c | 14 ++++++++++++++
> user/kvmctl.h | 5 +++++
> 3 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c
> index 59e79bf..6096f21 100644
> --- a/qemu/qemu-kvm.c
> +++ b/qemu/qemu-kvm.c
> @@ -697,6 +697,25 @@ int kvm_qemu_init()
> int kvm_qemu_create_context(void)
> {
> int i;
> + uint64_t ext;
> +
> + if (kvm_check_extension(kvm_context, &ext) < 0) {
> + kvm_qemu_destroy();
> + return -1;
> + }
> +
> + if (!(ext & KVM_EXTENSION_LAPIC) && kvm_apic_level) {
> + /*
> + * Opps... the kernel doesnt support apic-emulation even though
> + * the user wants it. We must turn this off and warn the user
> + */
> + kvm_apic_level = 0;
> +
> + /* FIXME: We should log this officially */
> + printf("WARNING: older kernel does not support apic " \
> + "emulation. Falling back to userspace emulation. Upgrade " \
> + "your kernel/modules\n");
> + }
>
The user may not be in a position to upgrade the kernel. Think distro
kernel and userspace. A warning is a bit severe.
>
> if (kvm_create(kvm_context, phys_ram_size, kvm_apic_level,
> (void**)&phys_ram_base) < 0) {
> diff --git a/user/kvmctl.c b/user/kvmctl.c
> index ea86426..fcabc1a 100644
> --- a/user/kvmctl.c
> +++ b/user/kvmctl.c
> @@ -889,3 +889,17 @@ int kvm_set_signal_mask(kvm_context_t kvm, int vcpu,
> const sigset_t *sigset)
> free(sigmask);
> return r;
> }
> +
> +int kvm_check_extension(kvm_context_t kvm, uint64_t *ext)
> +{
> + *ext = 0;
> +
> + int r = ioctl(kvm->fd, KVM_CHECK_EXTENSION, KVM_APIC_MSG);
> + if (r < 0)
> + return r;
>
-errno for new code, please.
> +
> + if (r)
> + *ext |= KVM_EXTENSION_LAPIC;
> +
> + return 0;
> +}
>
How about a struct with a field per extension instead of bitmasks?
--
error compiling committee.c: too many arguments to function
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