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linux/arch/arm64/include/asm/kvm_asm.h
Will Deacon b8cc6eb5bd KVM: arm64: Expose unshare hypercall to the host 
Introduce an unshare hypercall which can be used to unmap memory from
the hypervisor stage-1 in nVHE protected mode. This will be useful to
update the EL2 ownership state of pages during guest teardown, and
avoids keeping dangling mappings to unreferenced portions of memory.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-14-qperret@google.com
2021-12-16 12:58:57 +00:00

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2012,2013 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#ifndef __ARM_KVM_ASM_H__
#define __ARM_KVM_ASM_H__
#include <asm/hyp_image.h>
#include <asm/insn.h>
#include <asm/virt.h>
#define ARM_EXIT_WITH_SERROR_BIT 31
#define ARM_EXCEPTION_CODE(x) ((x) & ~(1U << ARM_EXIT_WITH_SERROR_BIT))
#define ARM_EXCEPTION_IS_TRAP(x) (ARM_EXCEPTION_CODE((x)) == ARM_EXCEPTION_TRAP)
#define ARM_SERROR_PENDING(x) !!((x) & (1U << ARM_EXIT_WITH_SERROR_BIT))
#define ARM_EXCEPTION_IRQ 0
#define ARM_EXCEPTION_EL1_SERROR 1
#define ARM_EXCEPTION_TRAP 2
#define ARM_EXCEPTION_IL 3
/* The hyp-stub will return this for any kvm_call_hyp() call */
#define ARM_EXCEPTION_HYP_GONE HVC_STUB_ERR
#define kvm_arm_exception_type \
{ARM_EXCEPTION_IRQ, "IRQ" }, \
{ARM_EXCEPTION_EL1_SERROR, "SERROR" }, \
{ARM_EXCEPTION_TRAP, "TRAP" }, \
{ARM_EXCEPTION_HYP_GONE, "HYP_GONE" }
/*
* Size of the HYP vectors preamble. kvm_patch_vector_branch() generates code
* that jumps over this.
*/
#define KVM_VECTOR_PREAMBLE (2 * AARCH64_INSN_SIZE)
#define KVM_HOST_SMCCC_ID(id) \
ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
ARM_SMCCC_SMC_64, \
ARM_SMCCC_OWNER_VENDOR_HYP, \
(id))
#define KVM_HOST_SMCCC_FUNC(name) KVM_HOST_SMCCC_ID(__KVM_HOST_SMCCC_FUNC_##name)
#define __KVM_HOST_SMCCC_FUNC___kvm_hyp_init 0
#ifndef __ASSEMBLY__
#include <linux/mm.h>
enum __kvm_host_smccc_func {
/* Hypercalls available only prior to pKVM finalisation */
/* __KVM_HOST_SMCCC_FUNC___kvm_hyp_init */
__KVM_HOST_SMCCC_FUNC___kvm_get_mdcr_el2 = __KVM_HOST_SMCCC_FUNC___kvm_hyp_init + 1,
__KVM_HOST_SMCCC_FUNC___pkvm_init,
__KVM_HOST_SMCCC_FUNC___pkvm_create_private_mapping,
__KVM_HOST_SMCCC_FUNC___pkvm_cpu_set_vector,
__KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs,
__KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs,
__KVM_HOST_SMCCC_FUNC___vgic_v3_get_gic_config,
__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___kvm_adjust_pc,
__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
__KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa,
__KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid,
__KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context,
__KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff,
__KVM_HOST_SMCCC_FUNC___vgic_v3_read_vmcr,
__KVM_HOST_SMCCC_FUNC___vgic_v3_write_vmcr,
__KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs,
__KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs,
__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_init_traps,
};
#define DECLARE_KVM_VHE_SYM(sym) extern char sym[]
#define DECLARE_KVM_NVHE_SYM(sym) extern char kvm_nvhe_sym(sym)[]
/*
* Define a pair of symbols sharing the same name but one defined in
* VHE and the other in nVHE hyp implementations.
*/
#define DECLARE_KVM_HYP_SYM(sym) \
DECLARE_KVM_VHE_SYM(sym); \
DECLARE_KVM_NVHE_SYM(sym)
#define DECLARE_KVM_VHE_PER_CPU(type, sym) \
DECLARE_PER_CPU(type, sym)
#define DECLARE_KVM_NVHE_PER_CPU(type, sym) \
DECLARE_PER_CPU(type, kvm_nvhe_sym(sym))
#define DECLARE_KVM_HYP_PER_CPU(type, sym) \
DECLARE_KVM_VHE_PER_CPU(type, sym); \
DECLARE_KVM_NVHE_PER_CPU(type, sym)
/*
* Compute pointer to a symbol defined in nVHE percpu region.
* Returns NULL if percpu memory has not been allocated yet.
*/
#define this_cpu_ptr_nvhe_sym(sym) per_cpu_ptr_nvhe_sym(sym, smp_processor_id())
#define per_cpu_ptr_nvhe_sym(sym, cpu) \
({ \
unsigned long base, off; \
base = kvm_arm_hyp_percpu_base[cpu]; \
off = (unsigned long)&CHOOSE_NVHE_SYM(sym) - \
(unsigned long)&CHOOSE_NVHE_SYM(__per_cpu_start); \
base ? (typeof(CHOOSE_NVHE_SYM(sym))*)(base + off) : NULL; \
})
#if defined(__KVM_NVHE_HYPERVISOR__)
#define CHOOSE_NVHE_SYM(sym) sym
#define CHOOSE_HYP_SYM(sym) CHOOSE_NVHE_SYM(sym)
/* The nVHE hypervisor shouldn't even try to access VHE symbols */
extern void *__nvhe_undefined_symbol;
#define CHOOSE_VHE_SYM(sym) __nvhe_undefined_symbol
#define this_cpu_ptr_hyp_sym(sym) (&__nvhe_undefined_symbol)
#define per_cpu_ptr_hyp_sym(sym, cpu) (&__nvhe_undefined_symbol)
#elif defined(__KVM_VHE_HYPERVISOR__)
#define CHOOSE_VHE_SYM(sym) sym
#define CHOOSE_HYP_SYM(sym) CHOOSE_VHE_SYM(sym)
/* The VHE hypervisor shouldn't even try to access nVHE symbols */
extern void *__vhe_undefined_symbol;
#define CHOOSE_NVHE_SYM(sym) __vhe_undefined_symbol
#define this_cpu_ptr_hyp_sym(sym) (&__vhe_undefined_symbol)
#define per_cpu_ptr_hyp_sym(sym, cpu) (&__vhe_undefined_symbol)
#else
/*
* BIG FAT WARNINGS:
*
* - Don't be tempted to change the following is_kernel_in_hyp_mode()
* to has_vhe(). has_vhe() is implemented as a *final* capability,
* while this is used early at boot time, when the capabilities are
* not final yet....
*
* - Don't let the nVHE hypervisor have access to this, as it will
* pick the *wrong* symbol (yes, it runs at EL2...).
*/
#define CHOOSE_HYP_SYM(sym) (is_kernel_in_hyp_mode() \
? CHOOSE_VHE_SYM(sym) \
: CHOOSE_NVHE_SYM(sym))
#define this_cpu_ptr_hyp_sym(sym) (is_kernel_in_hyp_mode() \
? this_cpu_ptr(&sym) \
: this_cpu_ptr_nvhe_sym(sym))
#define per_cpu_ptr_hyp_sym(sym, cpu) (is_kernel_in_hyp_mode() \
? per_cpu_ptr(&sym, cpu) \
: per_cpu_ptr_nvhe_sym(sym, cpu))
#define CHOOSE_VHE_SYM(sym) sym
#define CHOOSE_NVHE_SYM(sym) kvm_nvhe_sym(sym)
#endif
struct kvm_nvhe_init_params {
unsigned long mair_el2;
unsigned long tcr_el2;
unsigned long tpidr_el2;
unsigned long stack_hyp_va;
phys_addr_t pgd_pa;
unsigned long hcr_el2;
unsigned long vttbr;
unsigned long vtcr;
};
/* Translate a kernel address @ptr into its equivalent linear mapping */
#define kvm_ksym_ref(ptr) \
({ \
void *val = (ptr); \
if (!is_kernel_in_hyp_mode()) \
val = lm_alias((ptr)); \
val; \
})
#define kvm_ksym_ref_nvhe(sym) kvm_ksym_ref(kvm_nvhe_sym(sym))
struct kvm;
struct kvm_vcpu;
struct kvm_s2_mmu;
DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
#define __kvm_hyp_init CHOOSE_NVHE_SYM(__kvm_hyp_init)
#define __kvm_hyp_vector CHOOSE_HYP_SYM(__kvm_hyp_vector)
extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
DECLARE_KVM_NVHE_SYM(__per_cpu_start);
DECLARE_KVM_NVHE_SYM(__per_cpu_end);
DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
#define __bp_harden_hyp_vecs CHOOSE_HYP_SYM(__bp_harden_hyp_vecs)
extern void __kvm_flush_vm_context(void);
extern void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu);
extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa,
int level);
extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
extern void __kvm_timer_set_cntvoff(u64 cntvoff);
extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
extern void __kvm_adjust_pc(struct kvm_vcpu *vcpu);
extern u64 __vgic_v3_get_gic_config(void);
extern u64 __vgic_v3_read_vmcr(void);
extern void __vgic_v3_write_vmcr(u32 vmcr);
extern void __vgic_v3_init_lrs(void);
extern u64 __kvm_get_mdcr_el2(void);
#define __KVM_EXTABLE(from, to) \
" .pushsection __kvm_ex_table, \"a\"\n" \
" .align 3\n" \
" .long (" #from " - .), (" #to " - .)\n" \
" .popsection\n"
#define __kvm_at(at_op, addr) \
( { \
int __kvm_at_err = 0; \
u64 spsr, elr; \
asm volatile( \
" mrs %1, spsr_el2\n" \
" mrs %2, elr_el2\n" \
"1: at "at_op", %3\n" \
" isb\n" \
" b 9f\n" \
"2: msr spsr_el2, %1\n" \
" msr elr_el2, %2\n" \
" mov %w0, %4\n" \
"9:\n" \
__KVM_EXTABLE(1b, 2b) \
: "+r" (__kvm_at_err), "=&r" (spsr), "=&r" (elr) \
: "r" (addr), "i" (-EFAULT)); \
__kvm_at_err; \
} )
#else /* __ASSEMBLY__ */
.macro get_host_ctxt reg, tmp
adr_this_cpu \reg, kvm_host_data, \tmp
add \reg, \reg, #HOST_DATA_CONTEXT
.endm
.macro get_vcpu_ptr vcpu, ctxt
get_host_ctxt \ctxt, \vcpu
ldr \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
.endm
.macro get_loaded_vcpu vcpu, ctxt
adr_this_cpu \ctxt, kvm_hyp_ctxt, \vcpu
ldr \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
.endm
.macro set_loaded_vcpu vcpu, ctxt, tmp
adr_this_cpu \ctxt, kvm_hyp_ctxt, \tmp
str \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
.endm
/*
* KVM extable for unexpected exceptions.
* Create a struct kvm_exception_table_entry output to a section that can be
* mapped by EL2. The table is not sorted.
*
* The caller must ensure:
* x18 has the hypervisor value to allow any Shadow-Call-Stack instrumented
* code to write to it, and that SPSR_EL2 and ELR_EL2 are restored by the fixup.
*/
.macro _kvm_extable, from, to
.pushsection __kvm_ex_table, "a"
.align 3
.long (\from - .), (\to - .)
.popsection
.endm
#define CPU_XREG_OFFSET(x) (CPU_USER_PT_REGS + 8*x)
#define CPU_LR_OFFSET CPU_XREG_OFFSET(30)
#define CPU_SP_EL0_OFFSET (CPU_LR_OFFSET + 8)
/*
* We treat x18 as callee-saved as the host may use it as a platform
* register (e.g. for shadow call stack).
*/
.macro save_callee_saved_regs ctxt
str x18, [\ctxt, #CPU_XREG_OFFSET(18)]
stp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
stp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
stp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
stp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
stp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
stp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)]
.endm
.macro restore_callee_saved_regs ctxt
// We require \ctxt is not x18-x28
ldr x18, [\ctxt, #CPU_XREG_OFFSET(18)]
ldp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
ldp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
ldp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
ldp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
ldp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
ldp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)]
.endm
.macro save_sp_el0 ctxt, tmp
mrs \tmp, sp_el0
str \tmp, [\ctxt, #CPU_SP_EL0_OFFSET]
.endm
.macro restore_sp_el0 ctxt, tmp
ldr \tmp, [\ctxt, #CPU_SP_EL0_OFFSET]
msr sp_el0, \tmp
.endm
#endif
#endif /* __ARM_KVM_ASM_H__ */
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