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author | Marc Zyngier <maz@kernel.org> | 2021-03-09 12:29:24 +0000 |
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committer | Marc Zyngier <maz@kernel.org> | 2021-08-21 18:42:23 +0100 |
commit | 3987e8ad4c1d325e119622966d05f212800bd1d4 (patch) | |
tree | 7c450786fb589751a804080ac52c1443c1a4975b | |
parent | f09b5af8134b5e1728c5bc00f054b16907aa673c (diff) | |
download | kvmtool-m1-hacks.tar.gz |
kvmtool: arm64: Configure VM with the minimal required IPA spacem1-hacks
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 <maz@kernel.org>
-rw-r--r-- | arm/aarch64/kvm.c | 20 |
1 files changed, 19 insertions, 1 deletions
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); } |