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KVM: arm64: Consolidate stage-2 initialisation into a single function

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The initialisation of guest stage-2 page-tables is currently split
across two functions: kvm_init_stage2_mmu() and kvm_arm_setup_stage2().
That is presumably for historical reasons as kvm_arm_setup_stage2()
originates from the (now defunct) KVM port for 32-bit Arm.

Simplify this code path by merging both functions into one, taking care
to map the 'struct kvm' into the hypervisor stage-1 early on in order to
simplify the failure path.

Tested-by: Vincent Donnefort <vdonnefort@google.com>
Co-developed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-19-will@kernel.org
This commit is contained in:
Quentin Perret 2022-11-10 19:02:51 +00:00 • committed by Marc Zyngier
parent 717a7eebac
commit 315775ff7c
6 changed files with 41 additions and 48 deletions
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2
arch/arm64/include/asm/kvm_arm.h
View file

@ -135,7 +135,7 @@
* 40 bits wide (T0SZ = 24). Systems with a PARange smaller than 40 bits are
* not known to exist and will break with this configuration.
*
* The VTCR_EL2 is configured per VM and is initialised in kvm_arm_setup_stage2().
* The VTCR_EL2 is configured per VM and is initialised in kvm_init_stage2_mmu.
*
* Note that when using 4K pages, we concatenate two first level page tables
* together. With 16K pages, we concatenate 16 first level page tables.

2
arch/arm64/include/asm/kvm_host.h
View file

@ -990,8 +990,6 @@ int kvm_set_ipa_limit(void);
#define __KVM_HAVE_ARCH_VM_ALLOC
struct kvm *kvm_arch_alloc_vm(void);
int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type);
static inline bool kvm_vm_is_protected(struct kvm *kvm)
{
return false;

2
arch/arm64/include/asm/kvm_mmu.h
View file

@ -166,7 +166,7 @@ int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size,
void free_hyp_pgds(void);
void stage2_unmap_vm(struct kvm *kvm);
int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu);
int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long type);
void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu);
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
phys_addr_t pa, unsigned long size, bool writable);

27
arch/arm64/kvm/arm.c
View file

@ -139,28 +139,24 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
int ret;
ret = kvm_arm_setup_stage2(kvm, type);
if (ret)
return ret;
ret = kvm_init_stage2_mmu(kvm, &kvm->arch.mmu);
if (ret)
return ret;
ret = kvm_share_hyp(kvm, kvm + 1);
if (ret)
goto out_free_stage2_pgd;
return ret;
ret = pkvm_init_host_vm(kvm);
if (ret)
goto out_free_stage2_pgd;
goto err_unshare_kvm;
if (!zalloc_cpumask_var(&kvm->arch.supported_cpus, GFP_KERNEL)) {
ret = -ENOMEM;
goto out_free_stage2_pgd;
goto err_unshare_kvm;
}
cpumask_copy(kvm->arch.supported_cpus, cpu_possible_mask);
ret = kvm_init_stage2_mmu(kvm, &kvm->arch.mmu, type);
if (ret)
goto err_free_cpumask;
kvm_vgic_early_init(kvm);
/* The maximum number of VCPUs is limited by the host's GIC model */
@ -169,9 +165,12 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
set_default_spectre(kvm);
kvm_arm_init_hypercalls(kvm);
return ret;
out_free_stage2_pgd:
kvm_free_stage2_pgd(&kvm->arch.mmu);
return 0;
err_free_cpumask:
free_cpumask_var(kvm->arch.supported_cpus);
err_unshare_kvm:
kvm_unshare_hyp(kvm, kvm + 1);
return ret;
}

27
arch/arm64/kvm/mmu.c
View file

@ -675,15 +675,40 @@ static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
* kvm_init_stage2_mmu - Initialise a S2 MMU structure
* @kvm: The pointer to the KVM structure
* @mmu: The pointer to the s2 MMU structure
* @type: The machine type of the virtual machine
*
* Allocates only the stage-2 HW PGD level table(s).
* Note we don't need locking here as this is only called when the VM is
* created, which can only be done once.
*/
int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu)
int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long type)
{
u32 kvm_ipa_limit = get_kvm_ipa_limit();
int cpu, err;
struct kvm_pgtable *pgt;
u64 mmfr0, mmfr1;
u32 phys_shift;
if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
return -EINVAL;
phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
if (phys_shift) {
if (phys_shift > kvm_ipa_limit ||
phys_shift < ARM64_MIN_PARANGE_BITS)
return -EINVAL;
} else {
phys_shift = KVM_PHYS_SHIFT;
if (phys_shift > kvm_ipa_limit) {
pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
current->comm);
return -EINVAL;
}
}
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
if (mmu->pgt != NULL) {
kvm_err("kvm_arch already initialized?\n");

29
arch/arm64/kvm/reset.c
View file

@ -395,32 +395,3 @@ int kvm_set_ipa_limit(void)
return 0;
}
int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
{
u64 mmfr0, mmfr1;
u32 phys_shift;
if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
return -EINVAL;
phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
if (phys_shift) {
if (phys_shift > kvm_ipa_limit ||
phys_shift < ARM64_MIN_PARANGE_BITS)
return -EINVAL;
} else {
phys_shift = KVM_PHYS_SHIFT;
if (phys_shift > kvm_ipa_limit) {
pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
current->comm);
return -EINVAL;
}
}
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
return 0;
}