On Wed, 08 Jul 2015 18:42:01 -0400
Bandan Das <b...@redhat.com> wrote:
>
> If a Linux guest is assigned more memory than is supported
> by the host processor, the guest is unable to boot. That
> is expected, however, there's no message indicating the user
> what went wrong. This change prints a message to stderr if
> KVM has the corresponding capability.
>
> Reported-by: Laszlo Ersek <ler...@redhat.com>
> Signed-off-by: Bandan Das <b...@redhat.com>
> ---
> linux-headers/linux/kvm.h | 1 +
> target-i386/kvm.c | 6 ++++++
> 2 files changed, 7 insertions(+)
>
> diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> index 3bac873..6afad49 100644
> --- a/linux-headers/linux/kvm.h
> +++ b/linux-headers/linux/kvm.h
> @@ -817,6 +817,7 @@ struct kvm_ppc_smmu_info {
> #define KVM_CAP_DISABLE_QUIRKS 116
> #define KVM_CAP_X86_SMM 117
> #define KVM_CAP_MULTI_ADDRESS_SPACE 118
> +#define KVM_CAP_PHY_ADDR_WIDTH 119
>
> #ifdef KVM_CAP_IRQ_ROUTING
>
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 066d03d..66e3448 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -892,6 +892,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
> uint64_t shadow_mem;
> int ret;
> struct utsname utsname;
> + int max_phys_bits;
>
> ret = kvm_get_supported_msrs(s);
> if (ret < 0) {
> @@ -945,6 +946,11 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
> }
> }
>
> + max_phys_bits = kvm_check_extension(s, KVM_CAP_PHY_ADDR_WIDTH);
max_phys_bits seems generic enough and could be applied to other targets
as well.
making it a property of machine, would make accessing/manipulating it easier.
define default value for machine/TCG mode and when KVM is enabled
it would override/set its own limit.
then any board could easily access machine->max_gpa to make board specific
checks.
> + if (max_phys_bits && (1ULL << max_phys_bits) <= ram_size)
> + fprintf(stderr, "Warning: The amount of memory assigned to the guest
> "
> + "is more than that supported by the host CPU(s). Guest may be
> unstable.\n");
> +
> if (kvm_check_extension(s, KVM_CAP_X86_SMM)) {
> smram_machine_done.notify = register_smram_listener;
> qemu_add_machine_init_done_notifier(&smram_machine_done);
