[PATCH] hw/arm/boot: Set SCR_EL3.FGTEn when booting kernel

[Fabian Vogt]

Just like d7ef5e16a17c sets SCR_EL3.HXEn for FEAT_HCX, this commit
handles SCR_EL3.FGTEn for FEAT_FGT:

When we direct boot a kernel on a CPU which emulates EL3, we need to
set up the EL3 system registers as the Linux kernel documentation
specifies:
    https://www.kernel.org/doc/Documentation/arm64/booting.rst

> For CPUs with the Fine Grained Traps (FEAT_FGT) extension present:
> - If EL3 is present and the kernel is entered at EL2:
>   - SCR_EL3.FGTEn (bit 27) must be initialised to 0b1.

Signed-off-by: Fabian Vogt <fvogt@suse.de>
---
 hw/arm/boot.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 720f22531a..24fa169060 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -761,6 +761,10 @@ static void do_cpu_reset(void *opaque)
                     if (cpu_isar_feature(aa64_hcx, cpu)) {
                         env->cp15.scr_el3 |= SCR_HXEN;
                     }
+                    if (cpu_isar_feature(aa64_fgt, cpu)) {
+                        env->cp15.scr_el3 |= SCR_FGTEN;
+                    }
+
                     /* AArch64 kernels never boot in secure mode */
                     assert(!info->secure_boot);
                     /* This hook is only supported for AArch32 currently:
-- 
2.41.0