On 04/10/19 12:38, David Gibson wrote:
> In order to call RTAS functions on powerpc kvm-unit-tests relies on the
> RTAS blob supplied by qemu. But new versions of qemu don't supply an RTAS
> blob: since the normal way for guests to get RTAS is to call the guest
> firmware's instantiate-rtas function, we now rely on that guest firmware
> to provide the RTAS code itself.
>
> But qemu-kvm-tests bypasses the usual guest firmware to just run itself,
> so we can't get the rtas blob from SLOF.
>
> But.. in fact the RTAS blob under qemu is a bit of a sham anyway - it's
> a tiny wrapper that forwards the RTAS call to a hypercall. So, we can
> just invoke that hypercall directly.
>
> Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Would it be hard to call instantiate-rtas? I'm not sure if you have any
interest in running kvm-unit-tests on hypervisors that might have a
different way to process RTAS calls.
Paolo
> ---
> lib/powerpc/asm/hcall.h | 3 +++
> lib/powerpc/rtas.c | 6 +++---
> powerpc/cstart64.S | 20 ++++++++++++++++----
> 3 files changed, 22 insertions(+), 7 deletions(-)
>
> So.. "new versions of qemu" in this case means ones that incorporate
> the pull request I just sent today.
>
> diff --git a/lib/powerpc/asm/hcall.h b/lib/powerpc/asm/hcall.h
> index a8bd7e3..1173fea 100644
> --- a/lib/powerpc/asm/hcall.h
> +++ b/lib/powerpc/asm/hcall.h
> @@ -24,6 +24,9 @@
> #define H_RANDOM 0x300
> #define H_SET_MODE 0x31C
>
> +#define KVMPPC_HCALL_BASE 0xf000
> +#define KVMPPC_H_RTAS (KVMPPC_HCALL_BASE + 0x0)
> +
> #ifndef __ASSEMBLY__
> /*
> * hcall_have_broken_sc1 checks if we're on a host with a broken sc1.
> diff --git a/lib/powerpc/rtas.c b/lib/powerpc/rtas.c
> index 2e7e0da..41c0a24 100644
> --- a/lib/powerpc/rtas.c
> +++ b/lib/powerpc/rtas.c
> @@ -46,9 +46,9 @@ void rtas_init(void)
> prop = fdt_get_property(dt_fdt(), node,
> "linux,rtas-entry", &len);
> if (!prop) {
> - printf("%s: /rtas/linux,rtas-entry: %s\n",
> - __func__, fdt_strerror(len));
> - abort();
> + /* We don't have a qemu provided RTAS blob, enter_rtas
> + * will use H_RTAS directly */
> + return;
> }
> data = (u32 *)prop->data;
> rtas_entry = (unsigned long)fdt32_to_cpu(*data);
> diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S
> index ec673b3..972851f 100644
> --- a/powerpc/cstart64.S
> +++ b/powerpc/cstart64.S
> @@ -121,13 +121,25 @@ halt:
>
> .globl enter_rtas
> enter_rtas:
> + LOAD_REG_ADDR(r11, rtas_entry)
> + ld r10, 0(r11)
> +
> + cmpdi r10,0
> + bne external_rtas
> +
> + /* Use H_RTAS directly */
> + mr r4,r3
> + lis r3,KVMPPC_H_RTAS@h
> + ori r3,r3,KVMPPC_H_RTAS@l
> + b hcall
> +
> +external_rtas:
> + /* Use external RTAS blob */
> mflr r0
> std r0, 16(r1)
>
> - LOAD_REG_ADDR(r10, rtas_return_loc)
> - mtlr r10
> - LOAD_REG_ADDR(r11, rtas_entry)
> - ld r10, 0(r11)
> + LOAD_REG_ADDR(r11, rtas_return_loc)
> + mtlr r11
>
> mfmsr r11
> LOAD_REG_IMMEDIATE(r9, RTAS_MSR_MASK)
>
