[PATCH v3 08/23] kvm: arm64: Remove vector_ptr param of hyp-init

David Brazdil
2020-11-26T15:57:51Z

KVM precomputes the hyp VA of __kvm_hyp_host_vector, essentially a
constant (minus ASLR), before passing it to __kvm_hyp_init.
Now that we have alternatives for converting kimg VA to hyp VA, replace
this with computing the constant inside __kvm_hyp_init, thus removing
the need for an argument.

Signed-off-by: David Brazdil <dbrazdil@google.com>
---
arch/arm64/include/asm/kvm_asm.h | 2 --
arch/arm64/include/asm/kvm_mmu.h | 26 +++++++++++++++++++++++++-
arch/arm64/kvm/arm.c | 4 +---
arch/arm64/kvm/hyp/nvhe/hyp-init.S | 9 ++++++---
4 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 4a6a77d8d13e..531f9d04eefd 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -163,10 +163,8 @@ struct kvm_vcpu;
struct kvm_s2_mmu;

DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
-DECLARE_KVM_NVHE_SYM(__kvm_hyp_host_vector);
DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
#define __kvm_hyp_init CHOOSE_NVHE_SYM(__kvm_hyp_init)
-#define __kvm_hyp_host_vector CHOOSE_NVHE_SYM(__kvm_hyp_host_vector)
#define __kvm_hyp_vector CHOOSE_HYP_SYM(__kvm_hyp_vector)

extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 5168a0c516ae..6945faeb68ac 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -93,7 +93,31 @@ alternative_cb_end
/* reg = __pa(reg) */
sub \reg, \reg, \tmp
.endm
-
+
+/*
+ * Convert a kernel image address to a hyp VA
+ * reg: kernel address to be converted in place
+ * tmp: temporary register
+ *
+ * The actual code generation takes place in kvm_get_kimage_voffset, and
+ * the instructions below are only there to reserve the space and
+ * perform the register allocation (kvm_get_kimage_voffset uses the
+ * specific registers encoded in the instructions).
+ */
+.macro kimg_hyp_va reg, tmp
+alternative_cb kvm_update_kimg_phys_offset
+ movz \tmp, #0
+ movk \tmp, #0, lsl #16
+ movk \tmp, #0, lsl #32
+ movk \tmp, #0, lsl #48
+alternative_cb_end
+
+ sub \reg, \reg, \tmp
+ mov_q \tmp, PAGE_OFFSET
+ orr \reg, \reg, \tmp
+ kern_hyp_va \reg
+.endm
+
#else

#include <linux/pgtable.h>
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index b25035dc0478..cd6e5dec203f 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1355,7 +1355,6 @@ static void cpu_init_hyp_mode(void)
{
phys_addr_t pgd_ptr;
unsigned long hyp_stack_ptr;
- unsigned long vector_ptr;
unsigned long tpidr_el2;
struct arm_smccc_res res;

@@ -1373,7 +1372,6 @@ static void cpu_init_hyp_mode(void)
pgd_ptr = kvm_mmu_get_httbr();
hyp_stack_ptr = __this_cpu_read(kvm_arm_hyp_stack_page) + PAGE_SIZE;
hyp_stack_ptr = kern_hyp_va(hyp_stack_ptr);
- vector_ptr = (unsigned long)kern_hyp_va(kvm_ksym_ref(__kvm_hyp_host_vector));

/*
* Call initialization code, and switch to the full blown HYP code.
@@ -1383,7 +1381,7 @@ static void cpu_init_hyp_mode(void)
*/
BUG_ON(!system_capabilities_finalized());
arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__kvm_hyp_init),
- pgd_ptr, tpidr_el2, hyp_stack_ptr, vector_ptr, &res);
+ pgd_ptr, tpidr_el2, hyp_stack_ptr, &res);
WARN_ON(res.a0 != SMCCC_RET_SUCCESS);

/*
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index 17b58dbc3a2f..b3492a3c4232 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -50,7 +50,6 @@ __invalid:
* x1: HYP pgd
* x2: per-CPU offset
* x3: HYP stack
- * x4: HYP vectors
*/
__do_hyp_init:
/* Check for a stub HVC call */
@@ -134,9 +133,13 @@ alternative_else_nop_endif
msr sctlr_el2, x0
isb

- /* Set the stack and new vectors */
+ /* Set the stack */
mov sp, x3
- msr vbar_el2, x4
+
+ /* Set the host vector */
+ ldr x0, =__kvm_hyp_host_vector
+ kimg_hyp_va x0, x1
+ msr vbar_el2, x0

/* Hello, World! */
mov x0, #SMCCC_RET_SUCCESS
--
2.29.2.454.gaff20da3a2-goog