[PATCH 12/15] arm: KVM: Simplify HYP init

Marc Zyngier
2016-06-07T10:58:32Z

Just like for arm64, we can now make the HYP setup a lot simpler,
and we can now initialise it in one go (instead of the two
phases we currently have).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm/include/asm/kvm_host.h | 15 +++++--------
arch/arm/kvm/init.S | 49 ++++++++---------------------------------
2 files changed, 14 insertions(+), 50 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 020f4eb..eafbfd5 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -250,18 +250,13 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
* code. The init code doesn't need to preserve these
* registers as r0-r3 are already callee saved according to
* the AAPCS.
- * Note that we slightly misuse the prototype by casing the
+ * Note that we slightly misuse the prototype by casting the
* stack pointer to a void *.
- *
- * We don't have enough registers to perform the full init in
- * one go. Install the boot PGD first, and then install the
- * runtime PGD, stack pointer and vectors. The PGDs are always
- * passed as the third argument, in order to be passed into
- * r2-r3 to the init code (yes, this is compliant with the
- * PCS!).
- */

- kvm_call_hyp(NULL, 0, boot_pgd_ptr);
+ * The PGDs are always passed as the third argument, in order
+ * to be passed into r2-r3 to the init code (yes, this is
+ * compliant with the PCS!).
+ */

kvm_call_hyp((void*)hyp_stack_ptr, vector_ptr, pgd_ptr);
}
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 1f9ae17..b82a99d 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -32,23 +32,13 @@
* r2,r3 = Hypervisor pgd pointer
*
* The init scenario is:
- * - We jump in HYP with four parameters: boot HYP pgd, runtime HYP pgd,
- * runtime stack, runtime vectors
- * - Enable the MMU with the boot pgd
- * - Jump to a target into the trampoline page (remember, this is the same
- * physical page!)
- * - Now switch to the runtime pgd (same VA, and still the same physical
- * page!)
+ * - We jump in HYP with 3 parameters: runtime HYP pgd, runtime stack,
+ * runtime vectors
* - Invalidate TLBs
* - Set stack and vectors
+ * - Setup the page tables
+ * - Enable the MMU
* - Profit! (or eret, if you only care about the code).
- *
- * As we only have four registers available to pass parameters (and we
- * need six), we split the init in two phases:
- * - Phase 1: r0 = 0, r1 = 0, r2,r3 contain the boot PGD.
- * Provides the basic HYP init, and enable the MMU.
- * - Phase 2: r0 = ToS, r1 = vectors, r2,r3 contain the runtime PGD.
- * Switches to the runtime PGD, set stack and vectors.
*/

.text
@@ -68,8 +58,11 @@ __kvm_hyp_init:
W(b) .

__do_hyp_init:
- cmp r0, #0 @ We have a SP?
- bne phase2 @ Yes, second stage init
+ @ Set stack pointer
+ mov sp, r0
+
+ @ Set HVBAR to point to the HYP vectors
+ mcr p15, 4, r1, c12, c0, 0 @ HVBAR

@ Set the HTTBR to point to the hypervisor PGD pointer passed
mcrr p15, 4, rr_lo_hi(r2, r3), c2
@@ -114,33 +107,9 @@ __do_hyp_init:
THUMB( ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_TE) )
orr r1, r1, r2
orr r0, r0, r1
- isb
mcr p15, 4, r0, c1, c0, 0 @ HSCR
-
- @ End of init phase-1
- eret
-
-phase2:
- @ Set stack pointer
- mov sp, r0
-
- @ Set HVBAR to point to the HYP vectors
- mcr p15, 4, r1, c12, c0, 0 @ HVBAR
-
- @ Jump to the trampoline page
- ldr r0, =TRAMPOLINE_VA
- adr r1, target
- bfi r0, r1, #0, #PAGE_SHIFT
- ret r0
-
-target: @ We're now in the trampoline code, switch page tables
- mcrr p15, 4, rr_lo_hi(r2, r3), c2
isb

- @ Invalidate the old TLBs
- mcr p15, 4, r0, c8, c7, 0 @ TLBIALLH
- dsb ish
-
eret

.ltorg
--
2.1.4