There is some value in keeping the IPA space small, as it reduces the size of the stage-2 page tables.
Let's compute the required space at VM creation time, and inform the kernel of our requirements. Signed-off-by: Marc Zyngier <[email protected]> --- arm/aarch64/kvm.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/arm/aarch64/kvm.c b/arm/aarch64/kvm.c index d03a27f2..4e66a22e 100644 --- a/arm/aarch64/kvm.c +++ b/arm/aarch64/kvm.c @@ -3,6 +3,7 @@ #include <asm/image.h> #include <linux/byteorder.h> +#include <kvm/util.h> /* * Return the TEXT_OFFSET value that the guest kernel expects. Note @@ -59,5 +60,22 @@ int kvm__arch_get_ipa_limit(struct kvm *kvm) int kvm__get_vm_type(struct kvm *kvm) { - return KVM_VM_TYPE_ARM_IPA_SIZE(kvm__arch_get_ipa_limit(kvm)); + unsigned int ipa_bits, max_ipa_bits; + unsigned long max_ipa; + + /* If we're running on an old kernel, use 0 as the VM type */ + max_ipa_bits = kvm__arch_get_ipa_limit(kvm); + if (!max_ipa_bits) + return 0; + + /* Otherwise, compute the minimal required IPA size */ + max_ipa = ARM_MEMORY_AREA + kvm->cfg.ram_size - 1; + ipa_bits = max(32, fls_long(max_ipa)); + pr_debug("max_ipa %lx ipa_bits %d max_ipa_bits %d", + max_ipa, ipa_bits, max_ipa_bits); + + if (ipa_bits > max_ipa_bits) + die("Memory too large for this system (needs %d bits, %d available)", ipa_bits, max_ipa_bits); + + return KVM_VM_TYPE_ARM_IPA_SIZE(ipa_bits); } -- 2.30.2 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
