On Wed, Aug 27, 2025 at 4:11 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> target/arm/cpregs.h | 6 ++++
> target/arm/gdbstub.c | 5 ++++
> target/arm/helper.c | 53 +---------------------------------
> target/arm/tcg/translate-a64.c | 9 ++++++
> 4 files changed, 21 insertions(+), 52 deletions(-)
>
> diff --git a/target/arm/cpregs.h b/target/arm/cpregs.h
> index 7bdf6cf847..d34ed0d40b 100644
> --- a/target/arm/cpregs.h
> +++ b/target/arm/cpregs.h
> @@ -911,6 +911,12 @@ struct ARMCPRegInfo {
> */
> uint32_t nv2_redirect_offset;
>
> + /*
> + * With VHE, with E2H, at EL2, access to this EL0/EL1 reg redirects
> + * to the EL2 reg with the specified key.
> + */
> + uint32_t vhe_redir_to_el2;
> +
> /* This is used only by VHE. */
> void *opaque;
> /*
> diff --git a/target/arm/gdbstub.c b/target/arm/gdbstub.c
> index e2fc389170..3727dc01af 100644
> --- a/target/arm/gdbstub.c
> +++ b/target/arm/gdbstub.c
> @@ -249,6 +249,11 @@ static int arm_gdb_get_sysreg(CPUState *cs, GByteArray *buf, int reg)
> if (ri) {
> switch (cpreg_field_type(ri)) {
> case MO_64:
> + if (ri->vhe_redir_to_el2 &&
> + (arm_hcr_el2_eff(env) & HCR_E2H) &&
> + arm_current_el(env) == 2) {
> + ri = get_arm_cp_reginfo(cpu->cp_regs, ri->vhe_redir_to_el2);
> + }
> return gdb_get_reg64(buf, (uint64_t)read_raw_cp_reg(env, ri));
> case MO_32:
> return gdb_get_reg32(buf, (uint32_t)read_raw_cp_reg(env, ri));
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index d0ccc23811..3f69ce6cb5 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -4441,47 +4441,6 @@ static CPAccessResult access_el1nvvct(CPUARMState *env, const ARMCPRegInfo *ri,
> return e2h_access(env, ri, isread);
> }
>
> -/* Test if system register redirection is to occur in the current state. */
> -static bool redirect_for_e2h(CPUARMState *env)
> -{
> - return arm_current_el(env) == 2 && (arm_hcr_el2_eff(env) & HCR_E2H);
> -}
> -
> -static uint64_t el2_e2h_read(CPUARMState *env, const ARMCPRegInfo *ri)
> -{
> - CPReadFn *readfn;
> -
> - if (redirect_for_e2h(env)) {
> - /* Switch to the saved EL2 version of the register. */
> - ri = ri->opaque;
> - readfn = ri->readfn;
> - } else {
> - readfn = ri->orig_readfn;
> - }
> - if (readfn == NULL) {
> - readfn = raw_read;
> - }
> - return readfn(env, ri);
> -}
> -
> -static void el2_e2h_write(CPUARMState *env, const ARMCPRegInfo *ri,
> - uint64_t value)
> -{
> - CPWriteFn *writefn;
> -
> - if (redirect_for_e2h(env)) {
> - /* Switch to the saved EL2 version of the register. */
> - ri = ri->opaque;
> - writefn = ri->writefn;
> - } else {
> - writefn = ri->orig_writefn;
> - }
> - if (writefn == NULL) {
> - writefn = raw_write;
> - }
> - writefn(env, ri, value);
> -}
> -
> static uint64_t el2_e2h_e12_read(CPUARMState *env, const ARMCPRegInfo *ri)
> {
> /* Pass the EL1 register accessor its ri, not the EL12 alias ri */
> @@ -4657,17 +4616,7 @@ static void define_arm_vh_e2h_redirects_aliases(ARMCPU *cpu)
> (gpointer)(uintptr_t)a->new_key, new_reg);
> g_assert(ok);
>
> - src_reg->opaque = dst_reg;
> - src_reg->orig_readfn = src_reg->readfn ?: raw_read;
> - src_reg->orig_writefn = src_reg->writefn ?: raw_write;
> - if (!src_reg->raw_readfn) {
> - src_reg->raw_readfn = raw_read;
> - }
> - if (!src_reg->raw_writefn) {
> - src_reg->raw_writefn = raw_write;
> - }
> - src_reg->readfn = el2_e2h_read;
> - src_reg->writefn = el2_e2h_write;
> + src_reg->vhe_redir_to_el2 = a->dst_key;
> }
> }
> #endif
> diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
> index 8303f0dac2..8fcc74d151 100644
> --- a/target/arm/tcg/translate-a64.c
> +++ b/target/arm/tcg/translate-a64.c
> @@ -2573,6 +2573,15 @@ static void handle_sys(DisasContext *s, bool isread,
> }
> }
>
> + if (ri->vhe_redir_to_el2 && s->current_el == 2 && s->e2h) {
> + /*
> + * This one of the FOO_EL1 registers which redirect to FOO_EL2
> + * from EL2 when HCR_EL2.E2H is set.
> + */
> + key = ri->vhe_redir_to_el2;
> + ri = redirect_cpreg(s, key, isread);
> + }
> +
> if (ri->accessfn || (ri->fgt && s->fgt_active)) {
> /* Emit code to perform further access permissions checks at
> * runtime; this may result in an exception.
> --
> 2.43.0
>
>
This looks much better
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>