Commit 26117e4c authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

KVM: arm64: Introduce __pkvm_host_wrprotect_guest() 



Introduce a new hypercall to remove the write permission from a
non-protected guest stage-2 mapping. This will be used for e.g. enabling
dirty logging.

Tested-by: default avatarFuad Tabba <tabba@google.com>
Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20241218194059.3670226-14-qperret@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 34884a0a

arch/arm64/include/asm/kvm_asm.h

+1 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ enum __kvm_host_smccc_func { 
	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_guest,

	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest,

	__KVM_HOST_SMCCC_FUNC___pkvm_host_relax_perms_guest,

	__KVM_HOST_SMCCC_FUNC___pkvm_host_wrprotect_guest,

	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,

	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,

	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,

arch/arm64/kvm/hyp/include/nvhe/mem_protect.h

+1 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu, 
			    enum kvm_pgtable_prot prot);

int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);

int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot);

int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);



bool addr_is_memory(phys_addr_t phys);

int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);

arch/arm64/kvm/hyp/nvhe/hyp-main.c

+21 −0
Original line number Diff line number Diff line
@@ -283,6 +283,26 @@ static void handle___pkvm_host_relax_perms_guest(struct kvm_cpu_context *host_ct 
	cpu_reg(host_ctxt, 1) = ret;

}



static void handle___pkvm_host_wrprotect_guest(struct kvm_cpu_context *host_ctxt)

{

	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);

	DECLARE_REG(u64, gfn, host_ctxt, 2);

	struct pkvm_hyp_vm *hyp_vm;

	int ret = -EINVAL;



	if (!is_protected_kvm_enabled())

		goto out;



	hyp_vm = get_np_pkvm_hyp_vm(handle);

	if (!hyp_vm)

		goto out;



	ret = __pkvm_host_wrprotect_guest(gfn, hyp_vm);

	put_pkvm_hyp_vm(hyp_vm);

out:

	cpu_reg(host_ctxt, 1) = ret;

}



static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt)

{

	DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
@@ -495,6 +515,7 @@ static const hcall_t host_hcall[] = { 
	HANDLE_FUNC(__pkvm_host_share_guest),

	HANDLE_FUNC(__pkvm_host_unshare_guest),

	HANDLE_FUNC(__pkvm_host_relax_perms_guest),

	HANDLE_FUNC(__pkvm_host_wrprotect_guest),

	HANDLE_FUNC(__kvm_adjust_pc),

	HANDLE_FUNC(__kvm_vcpu_run),

	HANDLE_FUNC(__kvm_flush_vm_context),

arch/arm64/kvm/hyp/nvhe/mem_protect.c

+19 −0
Original line number Diff line number Diff line
@@ -1511,3 +1511,22 @@ int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_ 


	return ret;

}



int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *vm)

{

	u64 ipa = hyp_pfn_to_phys(gfn);

	u64 phys;

	int ret;



	host_lock_component();

	guest_lock_component(vm);



	ret = __check_host_shared_guest(vm, &phys, ipa);

	if (!ret)

		ret = kvm_pgtable_stage2_wrprotect(&vm->pgt, ipa, PAGE_SIZE);



	guest_unlock_component(vm);

	host_unlock_component();



	return ret;

}