korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-17 01:04:19 +08:00
Code Issues Packages Projects Releases Wiki Activity

arm64: KVM: Simplify HYP init/teardown

Browse Source 
Now that we only have the "merged page tables" case to deal with,
there is a bunch of things we can simplify in the HYP code (both
at init and teardown time).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Marc Zyngier 2016-06-30 18:40:44 +01:00 committed by Christoffer Dall
parent 0535a3e2b2
commit 3421e9d88d
5 changed files with 26 additions and 92 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
arch/arm64/include/asm/kvm_host.h
View File

@ -48,7 +48,6 @@
int __attribute_const__ kvm_target_cpu(void);
int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
int kvm_arch_dev_ioctl_check_extension(long ext);
unsigned long kvm_hyp_reset_entry(void);
void __extended_idmap_trampoline(phys_addr_t boot_pgd, phys_addr_t idmap_start);
struct kvm_arch {
@ -357,19 +356,14 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
* Call initialization code, and switch to the full blown
* HYP code.
*/
__kvm_call_hyp((void *)boot_pgd_ptr, pgd_ptr,
hyp_stack_ptr, vector_ptr);
__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr);
}
void __kvm_hyp_teardown(void);
static inline void __cpu_reset_hyp_mode(phys_addr_t boot_pgd_ptr,
phys_addr_t phys_idmap_start)
{
/*
* Call reset code, and switch back to stub hyp vectors.
* Uses __kvm_call_hyp() to avoid kaslr's kvm_ksym_ref() translation.
*/
__kvm_call_hyp((void *)kvm_hyp_reset_entry(),
boot_pgd_ptr, phys_idmap_start);
kvm_call_hyp(__kvm_hyp_teardown, phys_idmap_start);
}
static inline void kvm_arch_hardware_unsetup(void) {}

61
arch/arm64/kvm/hyp-init.S
View File

@ -53,10 +53,9 @@ __invalid:
b .
/*
* x0: HYP boot pgd
* x1: HYP pgd
* x2: HYP stack
* x3: HYP vectors
* x0: HYP pgd
* x1: HYP stack
* x2: HYP vectors
*/
__do_hyp_init:
@ -110,71 +109,27 @@ __do_hyp_init:
msr sctlr_el2, x4
isb
/* Skip the trampoline dance if we merged the boot and runtime PGDs */
cmp x0, x1
b.eq merged
/* MMU is now enabled. Get ready for the trampoline dance */
ldr x4, =TRAMPOLINE_VA
adr x5, target
bfi x4, x5, #0, #PAGE_SHIFT
br x4
target: /* We're now in the trampoline code, switch page tables */
msr ttbr0_el2, x1
isb
/* Invalidate the old TLBs */
tlbi alle2
dsb sy
merged:
/* Set the stack and new vectors */
kern_hyp_va x1
mov sp, x1
kern_hyp_va x2
mov sp, x2
kern_hyp_va x3
msr vbar_el2, x3
msr vbar_el2, x2
/* Hello, World! */
eret
ENDPROC(__kvm_hyp_init)
/*
* Reset kvm back to the hyp stub. This is the trampoline dance in
* reverse. If kvm used an extended idmap, __extended_idmap_trampoline
* calls this code directly in the idmap. In this case switching to the
* boot tables is a no-op.
*
* x0: HYP boot pgd
* x1: HYP phys_idmap_start
* Reset kvm back to the hyp stub.
*/
ENTRY(__kvm_hyp_reset)
/* We're in trampoline code in VA, switch back to boot page tables */
msr ttbr0_el2, x0
isb
/* Ensure the PA branch doesn't find a stale tlb entry or stale code. */
ic iallu
tlbi alle2
dsb sy
isb
/* Branch into PA space */
adr x0, 1f
bfi x1, x0, #0, #PAGE_SHIFT
br x1
/* We're now in idmap, disable MMU */
1: mrs x0, sctlr_el2
mrs x0, sctlr_el2
ldr x1, =SCTLR_ELx_FLAGS
bic x0, x0, x1 // Clear SCTL_M and etc
msr sctlr_el2, x0
isb
/* Invalidate the old TLBs */
tlbi alle2
dsb sy
/* Install stub vectors */
adr_l x0, __hyp_stub_vectors
msr vbar_el2, x0

19
arch/arm64/kvm/hyp/entry.S
View File

@ -164,22 +164,3 @@ alternative_endif
eret
ENDPROC(__fpsimd_guest_restore)
/*
* When using the extended idmap, we don't have a trampoline page we can use
* while we switch pages tables during __kvm_hyp_reset. Accessing the idmap
* directly would be ideal, but if we're using the extended idmap then the
* idmap is located above HYP_PAGE_OFFSET, and the address will be masked by
* kvm_call_hyp using kern_hyp_va.
*
* x0: HYP boot pgd
* x1: HYP phys_idmap_start
*/
ENTRY(__extended_idmap_trampoline)
mov x4, x1
adr_l x3, __kvm_hyp_reset
/* insert __kvm_hyp_reset()s offset into phys_idmap_start */
bfi x4, x3, #0, #PAGE_SHIFT
br x4
ENDPROC(__extended_idmap_trampoline)

15
arch/arm64/kvm/hyp/hyp-entry.S
View File

@ -62,6 +62,21 @@ ENTRY(__vhe_hyp_call)
isb
ret
ENDPROC(__vhe_hyp_call)
/*
* Compute the idmap address of __kvm_hyp_reset based on the idmap
* start passed as a parameter, and jump there.
*
* x0: HYP phys_idmap_start
*/
ENTRY(__kvm_hyp_teardown)
mov x4, x0
adr_l x3, __kvm_hyp_reset
/* insert __kvm_hyp_reset()s offset into phys_idmap_start */
bfi x4, x3, #0, #PAGE_SHIFT
br x4
ENDPROC(__kvm_hyp_teardown)
el1_sync: // Guest trapped into EL2
save_x0_to_x3

11
arch/arm64/kvm/reset.c
View File

@ -132,14 +132,3 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
/* Reset timer */
return kvm_timer_vcpu_reset(vcpu, cpu_vtimer_irq);
}
unsigned long kvm_hyp_reset_entry(void)
{
/*
* KVM is running with merged page tables, which don't have the
* trampoline page mapped. We know the idmap is still mapped,
* but can't be called into directly. Use
* __extended_idmap_trampoline to do the call.
*/
return (unsigned long)kvm_ksym_ref(__extended_idmap_trampoline);
}