Commit 733774b5 authored by Will Deacon's avatar Will Deacon Committed by Marc Zyngier
Browse files

KVM: arm64: Remove is_protected_kvm_enabled() checks from hypercalls 



When pKVM is not enabled, the host shouldn't issue pKVM-specific
hypercalls and so there's no point checking for this in the pKVM
hypercall handlers.

Remove the redundant is_protected_kvm_enabled() checks from each
hypercall and instead rejig the hypercall table so that the
pKVM-specific hypercalls are unreachable when pKVM is not being used.

Reviewed-by: default avatarQuentin Perret <qperret@google.com>
Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Tested-by: default avatarFuad Tabba <tabba@google.com>
Tested-by: default avatarMostafa Saleh <smostafa@google.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260330144841.26181-8-will@kernel.org


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 3a81a814

arch/arm64/include/asm/kvm_asm.h

+14 −10
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ 
#include <linux/mm.h>



enum __kvm_host_smccc_func {

	/* Hypercalls available only prior to pKVM finalisation */

	/* Hypercalls that are unavailable once pKVM has finalised. */

	/* __KVM_HOST_SMCCC_FUNC___kvm_hyp_init */

	__KVM_HOST_SMCCC_FUNC___pkvm_init = __KVM_HOST_SMCCC_FUNC___kvm_hyp_init + 1,

	__KVM_HOST_SMCCC_FUNC___pkvm_create_private_mapping,
@@ -60,16 +60,9 @@ enum __kvm_host_smccc_func { 
	__KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs,

	__KVM_HOST_SMCCC_FUNC___vgic_v3_get_gic_config,

	__KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize,

	__KVM_HOST_SMCCC_FUNC_MIN_PKVM = __KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize,



	/* 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___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___pkvm_host_test_clear_young_guest,

	__KVM_HOST_SMCCC_FUNC___pkvm_host_mkyoung_guest,

	/* Hypercalls that are always available and common to [nh]VHE/pKVM. */

	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,

	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,

	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
@@ -81,6 +74,17 @@ enum __kvm_host_smccc_func { 
	__KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff,

	__KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs,

	__KVM_HOST_SMCCC_FUNC___vgic_v3_restore_vmcr_aprs,

	__KVM_HOST_SMCCC_FUNC_MAX_NO_PKVM = __KVM_HOST_SMCCC_FUNC___vgic_v3_restore_vmcr_aprs,



	/* Hypercalls that are available only when pKVM has finalised. */

	__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___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___pkvm_host_test_clear_young_guest,

	__KVM_HOST_SMCCC_FUNC___pkvm_host_mkyoung_guest,

	__KVM_HOST_SMCCC_FUNC___pkvm_reserve_vm,

	__KVM_HOST_SMCCC_FUNC___pkvm_unreserve_vm,

	__KVM_HOST_SMCCC_FUNC___pkvm_init_vm,

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

+20 −43
Original line number Diff line number Diff line
@@ -169,9 +169,6 @@ static void handle___pkvm_vcpu_load(struct kvm_cpu_context *host_ctxt) 
	DECLARE_REG(u64, hcr_el2, host_ctxt, 3);

	struct pkvm_hyp_vcpu *hyp_vcpu;



	if (!is_protected_kvm_enabled())

		return;



	hyp_vcpu = pkvm_load_hyp_vcpu(handle, vcpu_idx);

	if (!hyp_vcpu)

		return;
@@ -188,12 +185,8 @@ static void handle___pkvm_vcpu_load(struct kvm_cpu_context *host_ctxt) 


static void handle___pkvm_vcpu_put(struct kvm_cpu_context *host_ctxt)

{

	struct pkvm_hyp_vcpu *hyp_vcpu;



	if (!is_protected_kvm_enabled())

		return;

	struct pkvm_hyp_vcpu *hyp_vcpu = pkvm_get_loaded_hyp_vcpu();



	hyp_vcpu = pkvm_get_loaded_hyp_vcpu();

	if (hyp_vcpu)

		pkvm_put_hyp_vcpu(hyp_vcpu);

}
@@ -257,9 +250,6 @@ static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt) 
	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;
@@ -281,9 +271,6 @@ static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_ctxt) 
	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;
@@ -301,9 +288,6 @@ static void handle___pkvm_host_relax_perms_guest(struct kvm_cpu_context *host_ct 
	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;
@@ -321,9 +305,6 @@ static void handle___pkvm_host_wrprotect_guest(struct kvm_cpu_context *host_ctxt 
	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;
@@ -343,9 +324,6 @@ static void handle___pkvm_host_test_clear_young_guest(struct kvm_cpu_context *ho 
	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;
@@ -362,9 +340,6 @@ static void handle___pkvm_host_mkyoung_guest(struct kvm_cpu_context *host_ctxt) 
	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;
@@ -424,12 +399,8 @@ static void handle___kvm_tlb_flush_vmid(struct kvm_cpu_context *host_ctxt) 
static void handle___pkvm_tlb_flush_vmid(struct kvm_cpu_context *host_ctxt)

{

	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);

	struct pkvm_hyp_vm *hyp_vm;



	if (!is_protected_kvm_enabled())

		return;

	struct pkvm_hyp_vm *hyp_vm = get_np_pkvm_hyp_vm(handle);



	hyp_vm = get_np_pkvm_hyp_vm(handle);

	if (!hyp_vm)

		return;
@@ -603,14 +574,6 @@ static const hcall_t host_hcall[] = { 
	HANDLE_FUNC(__vgic_v3_get_gic_config),

	HANDLE_FUNC(__pkvm_prot_finalize),



	HANDLE_FUNC(__pkvm_host_share_hyp),

	HANDLE_FUNC(__pkvm_host_unshare_hyp),

	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(__pkvm_host_test_clear_young_guest),

	HANDLE_FUNC(__pkvm_host_mkyoung_guest),

	HANDLE_FUNC(__kvm_adjust_pc),

	HANDLE_FUNC(__kvm_vcpu_run),

	HANDLE_FUNC(__kvm_flush_vm_context),
@@ -622,6 +585,15 @@ static const hcall_t host_hcall[] = { 
	HANDLE_FUNC(__kvm_timer_set_cntvoff),

	HANDLE_FUNC(__vgic_v3_save_aprs),

	HANDLE_FUNC(__vgic_v3_restore_vmcr_aprs),



	HANDLE_FUNC(__pkvm_host_share_hyp),

	HANDLE_FUNC(__pkvm_host_unshare_hyp),

	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(__pkvm_host_test_clear_young_guest),

	HANDLE_FUNC(__pkvm_host_mkyoung_guest),

	HANDLE_FUNC(__pkvm_reserve_vm),

	HANDLE_FUNC(__pkvm_unreserve_vm),

	HANDLE_FUNC(__pkvm_init_vm),
@@ -635,7 +607,7 @@ static const hcall_t host_hcall[] = { 
static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)

{

	DECLARE_REG(unsigned long, id, host_ctxt, 0);

	unsigned long hcall_min = 0;

	unsigned long hcall_min = 0, hcall_max = -1;

	hcall_t hfn;



	/*
@@ -647,14 +619,19 @@ static void handle_host_hcall(struct kvm_cpu_context *host_ctxt) 
	 * basis. This is all fine, however, since __pkvm_prot_finalize

	 * returns -EPERM after the first call for a given CPU.

	 */

	if (static_branch_unlikely(&kvm_protected_mode_initialized))

		hcall_min = __KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize;

	if (static_branch_unlikely(&kvm_protected_mode_initialized)) {

		hcall_min = __KVM_HOST_SMCCC_FUNC_MIN_PKVM;

	} else {

		hcall_max = __KVM_HOST_SMCCC_FUNC_MAX_NO_PKVM;

	}



	id &= ~ARM_SMCCC_CALL_HINTS;

	id -= KVM_HOST_SMCCC_ID(0);



	if (unlikely(id < hcall_min || id >= ARRAY_SIZE(host_hcall)))

	if (unlikely(id < hcall_min || id > hcall_max ||

		     id >= ARRAY_SIZE(host_hcall))) {

		goto inval;

	}



	hfn = host_hcall[id];

	if (unlikely(!hfn))