target/arm: Implement emulation of nested virtualization

[PATCH 19/35] target/arm: Treat LDTR* and STTR* as LDR/STR when NV, NV1 is 1, 1

Posted by Peter Maydell 11 months, 2 weeks ago

FEAT_NV requires (per I_JKLJK) that when HCR_EL2.{NV,NV1} is {1,1} the
unprivileged-access instructions LDTR, STTR etc behave as normal
loads and stores. Implement the check that handles this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/hflags.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/target/arm/tcg/hflags.c b/target/arm/tcg/hflags.c
index f33c0a12741..8f254bf9ccb 100644
--- a/target/arm/tcg/hflags.c
+++ b/target/arm/tcg/hflags.c
@@ -261,8 +261,10 @@ static CPUARMTBFlags rebuild_hflags_a64(CPUARMState *env, int el, int fp_el,
         switch (mmu_idx) {
         case ARMMMUIdx_E10_1:
         case ARMMMUIdx_E10_1_PAN:
-            /* TODO: ARMv8.3-NV */
-            DP_TBFLAG_A64(flags, UNPRIV, 1);
+            /* FEAT_NV: NV,NV1 == 1,1 means we don't do UNPRIV accesses */
+            if ((hcr & (HCR_NV | HCR_NV1)) != (HCR_NV | HCR_NV1)) {
+                DP_TBFLAG_A64(flags, UNPRIV, 1);
+            }
             break;
         case ARMMMUIdx_E20_2:
         case ARMMMUIdx_E20_2_PAN:
-- 
2.34.1

Re: [PATCH 19/35] target/arm: Treat LDTR* and STTR* as LDR/STR when NV, NV1 is 1, 1

Posted by Richard Henderson 11 months ago

On 12/18/23 22:32, Peter Maydell wrote:
> FEAT_NV requires (per I_JKLJK) that when HCR_EL2.{NV,NV1} is {1,1} the
> unprivileged-access instructions LDTR, STTR etc behave as normal
> loads and stores. Implement the check that handles this.
> 
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
>   target/arm/tcg/hflags.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~