[PATCH v2 7/8] KVM: arm64: Remove patching of fn pointers in hyp

David Brazdil
2021-01-05T18:07:13Z

Storing a function pointer in hyp now generates relocation information
used at early boot to convert the address to hyp VA. The existing
alternative-based conversion mechanism is therefore obsolete. Remove it
and simplify its users.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: David Brazdil <dbrazdil@google.com>
---
arch/arm64/include/asm/kvm_mmu.h | 18 ------------------
arch/arm64/kernel/image-vars.h | 1 -
arch/arm64/kvm/hyp/nvhe/hyp-main.c | 11 ++++-------
arch/arm64/kvm/va_layout.c | 6 ------
4 files changed, 4 insertions(+), 32 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index adadc468cc71..90873851f677 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -135,24 +135,6 @@ static __always_inline unsigned long __kern_hyp_va(unsigned long v)

#define kern_hyp_va(v) ((typeof(v))(__kern_hyp_va((unsigned long)(v))))

-static __always_inline unsigned long __kimg_hyp_va(unsigned long v)
-{
- unsigned long offset;
-
- asm volatile(ALTERNATIVE_CB("movz %0, #0\n"
- "movk %0, #0, lsl #16\n"
- "movk %0, #0, lsl #32\n"
- "movk %0, #0, lsl #48\n",
- kvm_update_kimg_phys_offset)
- : "=r" (offset));
-
- return __kern_hyp_va((v - offset) | PAGE_OFFSET);
-}
-
-#define kimg_fn_hyp_va(v) ((typeof(*v))(__kimg_hyp_va((unsigned long)(v))))
-
-#define kimg_fn_ptr(x) (typeof(x) **)(x)
-
/*
* We currently support using a VM-specified IPA size. For backward
* compatibility, the default IPA size is fixed to 40bits.
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index f676243abac6..23f1a557bd9f 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -64,7 +64,6 @@ __efistub__ctype = _ctype;
/* Alternative callbacks for init-time patching of nVHE hyp code. */
KVM_NVHE_ALIAS(kvm_patch_vector_branch);
KVM_NVHE_ALIAS(kvm_update_va_mask);
-KVM_NVHE_ALIAS(kvm_update_kimg_phys_offset);
KVM_NVHE_ALIAS(kvm_get_kimage_voffset);

/* Global kernel state accessed by nVHE hyp code. */
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index a906f9e2ff34..f012f8665ecc 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -108,9 +108,9 @@ static void handle___vgic_v3_restore_aprs(struct kvm_cpu_context *host_ctxt)

typedef void (*hcall_t)(struct kvm_cpu_context *);

-#define HANDLE_FUNC(x) [__KVM_HOST_SMCCC_FUNC_##x] = kimg_fn_ptr(handle_##x)
+#define HANDLE_FUNC(x) [__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x

-static const hcall_t *host_hcall[] = {
+static const hcall_t host_hcall[] = {
HANDLE_FUNC(__kvm_vcpu_run),
HANDLE_FUNC(__kvm_flush_vm_context),
HANDLE_FUNC(__kvm_tlb_flush_vmid_ipa),
@@ -130,7 +130,6 @@ 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);
- const hcall_t *kfn;
hcall_t hfn;

id -= KVM_HOST_SMCCC_ID(0);
@@ -138,13 +137,11 @@ static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)
if (unlikely(id >= ARRAY_SIZE(host_hcall)))
goto inval;

- kfn = host_hcall[id];
- if (unlikely(!kfn))
+ hfn = host_hcall[id];
+ if (unlikely(!hfn))
goto inval;

cpu_reg(host_ctxt, 0) = SMCCC_RET_SUCCESS;
-
- hfn = kimg_fn_hyp_va(kfn);
hfn(host_ctxt);

return;
diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c
index fee7dcd95d73..978301392d67 100644
--- a/arch/arm64/kvm/va_layout.c
+++ b/arch/arm64/kvm/va_layout.c
@@ -283,12 +283,6 @@ static void generate_mov_q(u64 val, __le32 *origptr, __le32 *updptr, int nr_inst
*updptr++ = cpu_to_le32(insn);
}

-void kvm_update_kimg_phys_offset(struct alt_instr *alt,
- __le32 *origptr, __le32 *updptr, int nr_inst)
-{
- generate_mov_q(kimage_voffset + PHYS_OFFSET, origptr, updptr, nr_inst);
-}
-
void kvm_get_kimage_voffset(struct alt_instr *alt,
__le32 *origptr, __le32 *updptr, int nr_inst)
{
--
2.29.2.729.g45daf8777d-goog