On Thu, Jun 30, 2016 at 01:31:52PM +0100, Marc Zyngier wrote: > On 28/06/16 22:50, Christoffer Dall wrote: > > On Tue, Jun 07, 2016 at 11:58:32AM +0100, Marc Zyngier wrote: > >> 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@xxxxxxx> > >> --- > >> 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 > > > > probably just call this HYP pgd, HYP stack, and HYP vectors now > > Yup. > > >> * - 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 > > > > how are we sure there are no stale entries in the TLB beyond the idmap > > region? Did we take care of this during kernel boot? What about > > hotplug/suspend stuff? > > This is done just before installing the page tables (not visible in this > patch). Hotplug/suspend goes through the same path as well, so it should > be all taken care of. > Right, ok. Thanks, -Christoffer -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
