[PATCH] hw/arm/boot: set CPTR_EL3.ESM and SCR_EL3.EnTP2 when booting Linux with EL3

[Jerome Forissier]

According to the Linux kernel booting.rst [1], CPTR_EL3.ESM and
SCR_EL3.EnTP2 must be initialized to 1 when EL3 is present and FEAT_SME
is advertised. This has to be taken care of when QEMU boots directly
into the kernel (i.e., "-M virt,secure=on -cpu max -kernel Image").

Cc: qemu-stable@nongnu.org
Fixes: 78cb9776662a ("target/arm: Enable SME for -cpu max")
Link: [1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/arm64/booting.rst?h=v6.0#n321
Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
---
 hw/arm/boot.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index ada2717f76..ee3858b673 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -763,6 +763,10 @@ static void do_cpu_reset(void *opaque)
                     if (cpu_isar_feature(aa64_sve, cpu)) {
                         env->cp15.cptr_el[3] |= R_CPTR_EL3_EZ_MASK;
                     }
+                    if (cpu_isar_feature(aa64_sme, cpu)) {
+                        env->cp15.cptr_el[3] |= R_CPTR_EL3_ESM_MASK;
+                        env->cp15.scr_el3 |= SCR_ENTP2;
+                    }
                     /* AArch64 kernels never boot in secure mode */
                     assert(!info->secure_boot);
                     /* This hook is only supported for AArch32 currently:
-- 
2.34.1