Commit 315775ff authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

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



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: default avatarVincent Donnefort <vdonnefort@google.com>
Co-developed-by: default avatarFuad Tabba <tabba@google.com>
Signed-off-by: default avatarFuad Tabba <tabba@google.com>
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-19-will@kernel.org
parent 717a7eeb

arch/arm64/include/asm/kvm_arm.h

+1 −1
Original line number Diff line number Diff line
@@ -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.

arch/arm64/include/asm/kvm_host.h

+0 −2
Original line number Diff line number Diff line
@@ -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;

arch/arm64/include/asm/kvm_mmu.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/arm64/kvm/arm.c

+13 −14
Original line number Diff line number Diff line
@@ -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;

}

arch/arm64/kvm/mmu.c

+26 −1
Original line number Diff line number Diff line
@@ -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");