Commit d0bd3e65 authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

KVM: arm64: Introduce __pkvm_host_share_guest() 



In preparation for handling guest stage-2 mappings at EL2, introduce a
new pKVM hypercall allowing to share pages with non-protected guests.

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/20241218194059.3670226-11-qperret@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent f7d03fcb

arch/arm64/include/asm/kvm_asm.h

+1 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ enum __kvm_host_smccc_func { 
	/* Hypercalls available after pKVM finalisation */

	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp,

	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp,

	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_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/include/asm/kvm_host.h

+3 −0
Original line number Diff line number Diff line
@@ -771,6 +771,9 @@ struct kvm_vcpu_arch { 
	/* Cache some mmu pages needed inside spinlock regions */

	struct kvm_mmu_memory_cache mmu_page_cache;



	/* Pages to top-up the pKVM/EL2 guest pool */

	struct kvm_hyp_memcache pkvm_memcache;



	/* Virtual SError ESR to restore when HCR_EL2.VSE is set */

	u64 vsesr_el2;

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

+2 −0
Original line number Diff line number Diff line
@@ -39,6 +39,8 @@ int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages); 
int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages);

int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages);

int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages);

int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,

			    enum kvm_pgtable_prot prot);



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/include/nvhe/memory.h

+3 −1
Original line number Diff line number Diff line
@@ -46,6 +46,8 @@ struct hyp_page { 


	/* Host (non-meta) state. Guarded by the host stage-2 lock. */

	enum pkvm_page_state host_state : 8;



	u32 host_share_guest_count;

};



extern u64 __hyp_vmemmap;
@@ -68,7 +70,7 @@ static inline phys_addr_t hyp_virt_to_phys(void *addr) 


static inline struct hyp_page *hyp_phys_to_page(phys_addr_t phys)

{

	BUILD_BUG_ON(sizeof(struct hyp_page) != sizeof(u32));

	BUILD_BUG_ON(sizeof(struct hyp_page) != sizeof(u64));

	return &hyp_vmemmap[hyp_phys_to_pfn(phys)];

}

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

+34 −0
Original line number Diff line number Diff line
@@ -211,6 +211,39 @@ static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt) 
	cpu_reg(host_ctxt, 1) =  ret;

}



static int pkvm_refill_memcache(struct pkvm_hyp_vcpu *hyp_vcpu)

{

	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;



	return refill_memcache(&hyp_vcpu->vcpu.arch.pkvm_memcache,

			       host_vcpu->arch.pkvm_memcache.nr_pages,

			       &host_vcpu->arch.pkvm_memcache);

}



static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt)

{

	DECLARE_REG(u64, pfn, host_ctxt, 1);

	DECLARE_REG(u64, gfn, host_ctxt, 2);

	DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 3);

	struct pkvm_hyp_vcpu *hyp_vcpu;

	int ret = -EINVAL;



	if (!is_protected_kvm_enabled())

		goto out;



	hyp_vcpu = pkvm_get_loaded_hyp_vcpu();

	if (!hyp_vcpu || pkvm_hyp_vcpu_is_protected(hyp_vcpu))

		goto out;



	ret = pkvm_refill_memcache(hyp_vcpu);

	if (ret)

		goto out;



	ret = __pkvm_host_share_guest(pfn, gfn, hyp_vcpu, prot);

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);
@@ -420,6 +453,7 @@ static const hcall_t host_hcall[] = { 


	HANDLE_FUNC(__pkvm_host_share_hyp),

	HANDLE_FUNC(__pkvm_host_unshare_hyp),

	HANDLE_FUNC(__pkvm_host_share_guest),

	HANDLE_FUNC(__kvm_adjust_pc),

	HANDLE_FUNC(__kvm_vcpu_run),

	HANDLE_FUNC(__kvm_flush_vm_context),