[RFC PATCH v1 2/2] KVM: arm64: Allow the RAS feature bit in ID_AA64PFR0_EL1 writable from userspace

[Shaoqin Huang <shahuang@redhat.com>]

Currently FEAT_RAS is not writable, this makes migration fail between
systems where this feature differ. Allow the FEAT_RAS writable in
ID_AA64PFR0_EL1 to let the migration possible when the RAS is differ
between two machines.

Also update the kselftest to test the RAS field.

Signed-off-by: Shaoqin Huang <shahuang@redhat.com>
---
 arch/arm64/kvm/sys_regs.c                         | 1 -
 tools/testing/selftests/kvm/aarch64/set_id_regs.c | 1 +
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b09f8ba3525b..51ff66a11793 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2364,7 +2364,6 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  .val = ~(ID_AA64PFR0_EL1_AMU |
 		   ID_AA64PFR0_EL1_MPAM |
 		   ID_AA64PFR0_EL1_SVE |
-		   ID_AA64PFR0_EL1_RAS |
 		   ID_AA64PFR0_EL1_GIC |
 		   ID_AA64PFR0_EL1_AdvSIMD |
 		   ID_AA64PFR0_EL1_FP), },
diff --git a/tools/testing/selftests/kvm/aarch64/set_id_regs.c b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
index d20981663831..d2dd78ce0e02 100644
--- a/tools/testing/selftests/kvm/aarch64/set_id_regs.c
+++ b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
@@ -126,6 +126,7 @@ static const struct reg_ftr_bits ftr_id_aa64pfr0_el1[] = {
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, CSV2, 0),
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, DIT, 0),
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, SEL2, 0),
+	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, RAS, 0),
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, EL3, 0),
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, EL2, 0),
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, EL1, 0),
-- 
2.40.1