On Thu, Jun 27, 2024 at 10:02 AM Atish Patra <ati...@rivosinc.com> wrote:
>
> From: Rajnesh Kanwal <rkan...@rivosinc.com>
>
> Combining riscv_cpu_set_virt_enabled() and riscv_cpu_set_mode()
> functions. This is to make complete mode change information
> available through a single function.
>
> This allows to easily differentiate between HS->VS, VS->HS
> and VS->VS transitions when executing state update codes.
> For example: One use-case which inspired this change is
> to update mode-specific instruction and cycle counters
> which requires information of both prev mode and current
> mode.
>
> Signed-off-by: Rajnesh Kanwal <rkan...@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
Alistair
> ---
> target/riscv/cpu.h | 2 +-
> target/riscv/cpu_helper.c | 57
> +++++++++++++++++++++++------------------------
> target/riscv/op_helper.c | 17 +++++---------
> 3 files changed, 35 insertions(+), 41 deletions(-)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 90b8f1b08f83..46faefd24e09 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -544,7 +544,7 @@ void riscv_cpu_set_aia_ireg_rmw_fn(CPURISCVState *env,
> uint32_t priv,
> RISCVException smstateen_acc_ok(CPURISCVState *env, int index, uint64_t bit);
> #endif /* !CONFIG_USER_ONLY */
>
> -void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv);
> +void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv, bool
> virt_en);
>
> void riscv_translate_init(void);
> G_NORETURN void riscv_raise_exception(CPURISCVState *env,
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index 6709622dd3ab..10d3fdaed376 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -619,30 +619,6 @@ void riscv_cpu_set_geilen(CPURISCVState *env,
> target_ulong geilen)
> env->geilen = geilen;
> }
>
> -/* This function can only be called to set virt when RVH is enabled */
> -void riscv_cpu_set_virt_enabled(CPURISCVState *env, bool enable)
> -{
> - /* Flush the TLB on all virt mode changes. */
> - if (env->virt_enabled != enable) {
> - tlb_flush(env_cpu(env));
> - }
> -
> - env->virt_enabled = enable;
> -
> - if (enable) {
> - /*
> - * The guest external interrupts from an interrupt controller are
> - * delivered only when the Guest/VM is running (i.e. V=1). This means
> - * any guest external interrupt which is triggered while the Guest/VM
> - * is not running (i.e. V=0) will be missed on QEMU resulting in
> guest
> - * with sluggish response to serial console input and other I/O
> events.
> - *
> - * To solve this, we check and inject interrupt after setting V=1.
> - */
> - riscv_cpu_update_mip(env, 0, 0);
> - }
> -}
> -
> int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint64_t interrupts)
> {
> CPURISCVState *env = &cpu->env;
> @@ -715,7 +691,7 @@ void riscv_cpu_set_aia_ireg_rmw_fn(CPURISCVState *env,
> uint32_t priv,
> }
> }
>
> -void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv)
> +void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv, bool
> virt_en)
> {
> g_assert(newpriv <= PRV_M && newpriv != PRV_RESERVED);
>
> @@ -736,6 +712,28 @@ void riscv_cpu_set_mode(CPURISCVState *env, target_ulong
> newpriv)
> * preemptive context switch. As a result, do both.
> */
> env->load_res = -1;
> +
> + if (riscv_has_ext(env, RVH)) {
> + /* Flush the TLB on all virt mode changes. */
> + if (env->virt_enabled != virt_en) {
> + tlb_flush(env_cpu(env));
> + }
> +
> + env->virt_enabled = virt_en;
> + if (virt_en) {
> + /*
> + * The guest external interrupts from an interrupt controller are
> + * delivered only when the Guest/VM is running (i.e. V=1). This
> + * means any guest external interrupt which is triggered while
> the
> + * Guest/VM is not running (i.e. V=0) will be missed on QEMU
> + * resulting in guest with sluggish response to serial console
> + * input and other I/O events.
> + *
> + * To solve this, we check and inject interrupt after setting
> V=1.
> + */
> + riscv_cpu_update_mip(env, 0, 0);
> + }
> + }
> }
>
> /*
> @@ -1648,6 +1646,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
> {
> RISCVCPU *cpu = RISCV_CPU(cs);
> CPURISCVState *env = &cpu->env;
> + bool virt = env->virt_enabled;
> bool write_gva = false;
> uint64_t s;
>
> @@ -1778,7 +1777,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
>
> htval = env->guest_phys_fault_addr;
>
> - riscv_cpu_set_virt_enabled(env, 0);
> + virt = false;
> } else {
> /* Trap into HS mode */
> env->hstatus = set_field(env->hstatus, HSTATUS_SPV, false);
> @@ -1799,7 +1798,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
> env->htinst = tinst;
> env->pc = (env->stvec >> 2 << 2) +
> ((async && (env->stvec & 3) == 1) ? cause * 4 : 0);
> - riscv_cpu_set_mode(env, PRV_S);
> + riscv_cpu_set_mode(env, PRV_S, virt);
> } else {
> /* handle the trap in M-mode */
> if (riscv_has_ext(env, RVH)) {
> @@ -1815,7 +1814,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
> mtval2 = env->guest_phys_fault_addr;
>
> /* Trapping to M mode, virt is disabled */
> - riscv_cpu_set_virt_enabled(env, 0);
> + virt = false;
> }
>
> s = env->mstatus;
> @@ -1830,7 +1829,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
> env->mtinst = tinst;
> env->pc = (env->mtvec >> 2 << 2) +
> ((async && (env->mtvec & 3) == 1) ? cause * 4 : 0);
> - riscv_cpu_set_mode(env, PRV_M);
> + riscv_cpu_set_mode(env, PRV_M, virt);
> }
>
> /*
> diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
> index 2baf5bc3ca19..ec1408ba0fb1 100644
> --- a/target/riscv/op_helper.c
> +++ b/target/riscv/op_helper.c
> @@ -264,7 +264,7 @@ void helper_cbo_inval(CPURISCVState *env, target_ulong
> address)
> target_ulong helper_sret(CPURISCVState *env)
> {
> uint64_t mstatus;
> - target_ulong prev_priv, prev_virt;
> + target_ulong prev_priv, prev_virt = env->virt_enabled;
>
> if (!(env->priv >= PRV_S)) {
> riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
> @@ -307,11 +307,9 @@ target_ulong helper_sret(CPURISCVState *env)
> if (prev_virt) {
> riscv_cpu_swap_hypervisor_regs(env);
> }
> -
> - riscv_cpu_set_virt_enabled(env, prev_virt);
> }
>
> - riscv_cpu_set_mode(env, prev_priv);
> + riscv_cpu_set_mode(env, prev_priv, prev_virt);
>
> return retpc;
> }
> @@ -347,16 +345,13 @@ target_ulong helper_mret(CPURISCVState *env)
> mstatus = set_field(mstatus, MSTATUS_MPRV, 0);
> }
> env->mstatus = mstatus;
> - riscv_cpu_set_mode(env, prev_priv);
> -
> - if (riscv_has_ext(env, RVH)) {
> - if (prev_virt) {
> - riscv_cpu_swap_hypervisor_regs(env);
> - }
>
> - riscv_cpu_set_virt_enabled(env, prev_virt);
> + if (riscv_has_ext(env, RVH) && prev_virt) {
> + riscv_cpu_swap_hypervisor_regs(env);
> }
>
> + riscv_cpu_set_mode(env, prev_priv, prev_virt);
> +
> return retpc;
> }
>
>
> --
> 2.34.1
>
>
