This change adds support for inserting virtual interrupts from HS-mode
into VS-mode using hvien and hvip csrs. This also allows for IRQ filtering
from HS-mode.
Also, the spec doesn't mandate the interrupt to be actually supported
in hardware. Which allows HS-mode to assert virtual interrupts to VS-mode
that have no connection to any real interrupt events.
This is defined as part of the AIA specification [0], "6.3.2 Virtual
interrupts for VS level".
[0]:
https://github.com/riscv/riscv-aia/releases/download/1.0-RC4/riscv-interrupts-1.0-RC4.pdf
Signed-off-by: Rajnesh Kanwal <rkanwal@rivosinc.com>
---
target/riscv/cpu.c | 3 +-
target/riscv/cpu.h | 14 +++
target/riscv/cpu_helper.c | 48 +++++++---
target/riscv/csr.c | 196 ++++++++++++++++++++++++++++++++++----
target/riscv/machine.c | 3 +
5 files changed, 234 insertions(+), 30 deletions(-)
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 9557194a21..c2b05d4c37 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -713,7 +713,8 @@ static bool riscv_cpu_has_work(CPUState *cs)
* mode and delegation registers, but respect individual enables
*/
return riscv_cpu_all_pending(env) != 0 ||
- riscv_cpu_sirq_pending(env) != RISCV_EXCP_NONE;
+ riscv_cpu_sirq_pending(env) != RISCV_EXCP_NONE ||
+ riscv_cpu_vsirq_pending(env) != RISCV_EXCP_NONE;
#else
return true;
#endif
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 07cf656471..3e10eee38f 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -196,6 +196,12 @@ struct CPUArchState {
*/
uint64_t sie;
+ /*
+ * When hideleg[i]=0 and hvien[i]=1, vsie[i] is no more
+ * alias of sie[i] (mie[i]) and needs to be maintained separatly.
+ */
+ uint64_t vsie;
+
target_ulong satp; /* since: priv-1.10.0 */
target_ulong stval;
target_ulong medeleg;
@@ -230,6 +236,14 @@ struct CPUArchState {
target_ulong hgeie;
target_ulong hgeip;
uint64_t htimedelta;
+ uint64_t hvien;
+
+ /*
+ * Bits VSSIP, VSTIP and VSEIP in hvip are maintained in mip. Other bits
+ * from 0:12 are reserved. Bits 13:63 are not aliased and must be
separately
+ * maintain in hvip.
+ */
+ uint64_t hvip;
/* Hypervisor controlled virtual interrupt priorities */
target_ulong hvictl;
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 681b4ae811..80bdd4cf5a 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -366,8 +366,9 @@ static int riscv_cpu_pending_to_irq(CPURISCVState *env,
}
/*
- * Doesn't report interrupts inserted using mvip from M-mode firmware. Those
- * are returned in riscv_cpu_sirq_pending().
+ * Doesn't report interrupts inserted using mvip from M-mode firmware or
+ * using hvip bits 13:63 from HS-mode. Those are returned in
+ * riscv_cpu_sirq_pending() and riscv_cpu_vsirq_pending().
*/
uint64_t riscv_cpu_all_pending(CPURISCVState *env)
{
@@ -399,16 +400,23 @@ int riscv_cpu_sirq_pending(CPURISCVState *env)
int riscv_cpu_vsirq_pending(CPURISCVState *env)
{
- uint64_t irqs = riscv_cpu_all_pending(env) & env->mideleg &
- (MIP_VSSIP | MIP_VSTIP | MIP_VSEIP);
+ uint64_t irqs = riscv_cpu_all_pending(env) & env->mideleg & env->hideleg;
+ uint64_t irqs_f_vs = env->hvip & env->hvien & ~env->hideleg & env->vsie;
+ uint64_t vsbits;
+
+ /* Bring VS-level bits to correct position */
+ vsbits = irqs & VS_MODE_INTERRUPTS;
+ irqs &= ~VS_MODE_INTERRUPTS;
+ irqs |= vsbits >> 1;
return riscv_cpu_pending_to_irq(env, IRQ_S_EXT, IPRIO_DEFAULT_S,
- irqs >> 1, env->hviprio);
+ (irqs | irqs_f_vs), env->hviprio);
}
static int riscv_cpu_local_irq_pending(CPURISCVState *env)
{
- uint64_t irqs, pending, mie, hsie, vsie, irqs_f;
+ uint64_t irqs, pending, mie, hsie, vsie, irqs_f, irqs_f_vs;
+ uint64_t vsbits, irq_delegated;
int virq;
/* Determine interrupt enable state of all privilege modes */
@@ -445,12 +453,26 @@ static int riscv_cpu_local_irq_pending(CPURISCVState *env)
irqs, env->siprio);
}
+ /* Check for virtual VS-mode interrupts. */
+ irqs_f_vs = env->hvip & env->hvien & ~env->hideleg & env->vsie;
+
/* Check VS-mode interrupts */
- irqs = pending & env->mideleg & env->hideleg & -vsie;
+ irq_delegated = pending & env->mideleg & env->hideleg;
+
+ /* Bring VS-level bits to correct position */
+ vsbits = irq_delegated & VS_MODE_INTERRUPTS;
+ irq_delegated &= ~VS_MODE_INTERRUPTS;
+ irq_delegated |= vsbits >> 1;
+
+ irqs = (irq_delegated | irqs_f_vs) & -vsie;
if (irqs) {
virq = riscv_cpu_pending_to_irq(env, IRQ_S_EXT, IPRIO_DEFAULT_S,
- irqs >> 1, env->hviprio);
- return (virq <= 0) ? virq : virq + 1;
+ irqs, env->hviprio);
+ if (virq <= 0 || (virq > 12 && virq <= 63)) {
+ return virq;
+ } else {
+ return virq + 1;
+ }
}
/* Indicate no pending interrupt */
@@ -625,6 +647,7 @@ void riscv_cpu_interrupt(CPURISCVState *env)
if (env->virt_enabled) {
gein = get_field(env->hstatus, HSTATUS_VGEIN);
vsgein = (env->hgeip & (1ULL << gein)) ? MIP_VSEIP : 0;
+ irqf = env->hvien & env->hvip & env->vsie;
} else {
irqf = env->mvien & env->mvip & env->sie;
}
@@ -1620,6 +1643,8 @@ void riscv_cpu_do_interrupt(CPUState *cs)
uint64_t deleg = async ? env->mideleg : env->medeleg;
bool s_injected = env->mvip & (1 << cause) & env->mvien &&
!(env->mip & (1 << cause));
+ bool vs_injected = env->hvip & (1 << cause) & env->hvien &&
+ !(env->mip & (1 << cause));
target_ulong tval = 0;
target_ulong tinst = 0;
target_ulong htval = 0;
@@ -1711,12 +1736,13 @@ void riscv_cpu_do_interrupt(CPUState *cs)
riscv_cpu_get_trap_name(cause, async));
if (env->priv <= PRV_S && cause < 64 &&
- (((deleg >> cause) & 1) || s_injected)) {
+ (((deleg >> cause) & 1) || s_injected || vs_injected)) {
/* handle the trap in S-mode */
if (riscv_has_ext(env, RVH)) {
uint64_t hdeleg = async ? env->hideleg : env->hedeleg;
- if (env->virt_enabled && ((hdeleg >> cause) & 1)) {
+ if (env->virt_enabled &&
+ (((hdeleg >> cause) & 1) || vs_injected)) {
/* Trap to VS mode */
/*
* See if we need to adjust cause. Yes if its VS mode
interrupt
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index c1ca065a81..1929d5fa7b 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -30,6 +30,11 @@
#include "qemu/guest-random.h"
#include "qapi/error.h"
+
+static RISCVException rmw_hvip64(CPURISCVState *env, int csrno,
+ uint64_t *ret_val,
+ uint64_t new_val, uint64_t wr_mask);
+
/* CSR function table public API */
void riscv_get_csr_ops(int csrno, riscv_csr_operations *ops)
{
@@ -1176,6 +1181,8 @@ static const target_ulong sip_writable_mask = SIP_SSIP |
LOCAL_INTERRUPTS;
static const target_ulong hip_writable_mask = MIP_VSSIP;
static const target_ulong hvip_writable_mask = MIP_VSSIP | MIP_VSTIP |
MIP_VSEIP | LOCAL_INTERRUPTS;
+static const target_ulong hvien_writable_mask = LOCAL_INTERRUPTS;
+
static const target_ulong vsip_writable_mask = MIP_VSSIP | LOCAL_INTERRUPTS;
const bool valid_vm_1_10_32[16] = {
@@ -2584,16 +2591,36 @@ static RISCVException rmw_vsie64(CPURISCVState *env,
int csrno,
uint64_t *ret_val,
uint64_t new_val, uint64_t wr_mask)
{
+ uint64_t alias_mask = (LOCAL_INTERRUPTS | VS_MODE_INTERRUPTS) &
+ env->hideleg;
+ uint64_t nalias_mask = LOCAL_INTERRUPTS & (~env->hideleg & env->hvien);
+ uint64_t rval, rval_vs, vsbits;
+ uint64_t wr_mask_vsie;
+ uint64_t wr_mask_mie;
RISCVException ret;
- uint64_t rval, mask = env->hideleg & VS_MODE_INTERRUPTS;
/* Bring VS-level bits to correct position */
- new_val = (new_val & (VS_MODE_INTERRUPTS >> 1)) << 1;
- wr_mask = (wr_mask & (VS_MODE_INTERRUPTS >> 1)) << 1;
+ vsbits = new_val & (VS_MODE_INTERRUPTS >> 1);
+ new_val &= ~(VS_MODE_INTERRUPTS >> 1);
+ new_val |= vsbits << 1;
+
+ vsbits = wr_mask & (VS_MODE_INTERRUPTS >> 1);
+ wr_mask &= ~(VS_MODE_INTERRUPTS >> 1);
+ wr_mask |= vsbits << 1;
+
+ wr_mask_mie = wr_mask & alias_mask;
+ wr_mask_vsie = wr_mask & nalias_mask;
+
+ ret = rmw_mie64(env, csrno, &rval, new_val, wr_mask_mie);
+
+ rval_vs = env->vsie & nalias_mask;
+ env->vsie = (env->vsie & ~wr_mask_vsie) | (new_val & wr_mask_vsie);
- ret = rmw_mie64(env, csrno, &rval, new_val, wr_mask & mask);
if (ret_val) {
- *ret_val = (rval & mask) >> 1;
+ rval &= alias_mask;
+ vsbits = rval & VS_MODE_INTERRUPTS;
+ rval &= ~VS_MODE_INTERRUPTS;
+ *ret_val = rval | (vsbits >> 1) | rval_vs;
}
return ret;
@@ -2812,15 +2839,26 @@ static RISCVException rmw_vsip64(CPURISCVState *env,
int csrno,
{
RISCVException ret;
uint64_t rval, mask = env->hideleg & VS_MODE_INTERRUPTS;
+ uint64_t vsbits;
- /* Bring VS-level bits to correct position */
- new_val = (new_val & (VS_MODE_INTERRUPTS >> 1)) << 1;
- wr_mask = (wr_mask & (VS_MODE_INTERRUPTS >> 1)) << 1;
+ /* Add virtualized bits into vsip mask. */
+ mask |= env->hvien & ~env->hideleg;
- ret = rmw_mip64(env, csrno, &rval, new_val,
- wr_mask & mask & vsip_writable_mask);
+ /* Bring VS-level bits to correct position */
+ vsbits = new_val & (VS_MODE_INTERRUPTS >> 1);
+ new_val &= ~(VS_MODE_INTERRUPTS >> 1);
+ new_val |= vsbits << 1;
+ vsbits = wr_mask & (VS_MODE_INTERRUPTS >> 1);
+ wr_mask &= ~(VS_MODE_INTERRUPTS >> 1);
+ wr_mask |= vsbits << 1;
+
+ ret = rmw_hvip64(env, csrno, &rval, new_val,
+ wr_mask & mask & vsip_writable_mask);
if (ret_val) {
- *ret_val = (rval & mask) >> 1;
+ rval &= mask;
+ vsbits = rval & VS_MODE_INTERRUPTS;
+ rval &= ~VS_MODE_INTERRUPTS;
+ *ret_val = rval | (vsbits >> 1);
}
return ret;
@@ -3112,6 +3150,52 @@ static RISCVException write_hedeleg(CPURISCVState *env,
int csrno,
return RISCV_EXCP_NONE;
}
+static RISCVException rmw_hvien64(CPURISCVState *env, int csrno,
+ uint64_t *ret_val,
+ uint64_t new_val, uint64_t wr_mask)
+{
+ uint64_t mask = wr_mask & hvien_writable_mask;
+
+ if (ret_val) {
+ *ret_val = env->hvien;
+ }
+
+ env->hvien = (env->hvien & ~mask) | (new_val & mask);
+
+ return RISCV_EXCP_NONE;
+}
+
+static RISCVException rmw_hvien(CPURISCVState *env, int csrno,
+ target_ulong *ret_val,
+ target_ulong new_val, target_ulong wr_mask)
+{
+ uint64_t rval;
+ RISCVException ret;
+
+ ret = rmw_hvien64(env, csrno, &rval, new_val, wr_mask);
+ if (ret_val) {
+ *ret_val = rval;
+ }
+
+ return ret;
+}
+
+static RISCVException rmw_hvienh(CPURISCVState *env, int csrno,
+ target_ulong *ret_val,
+ target_ulong new_val, target_ulong wr_mask)
+{
+ uint64_t rval;
+ RISCVException ret;
+
+ ret = rmw_hvien64(env, csrno, &rval,
+ ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
+ if (ret_val) {
+ *ret_val = rval >> 32;
+ }
+
+ return ret;
+}
+
static RISCVException rmw_hideleg64(CPURISCVState *env, int csrno,
uint64_t *ret_val,
uint64_t new_val, uint64_t wr_mask)
@@ -3157,16 +3241,94 @@ static RISCVException rmw_hidelegh(CPURISCVState *env,
int csrno,
return ret;
}
+/*
+ * The function is written for two use-cases:
+ * 1- To access hvip csr as is for HS-mode access.
+ * 2- To access vsip as a combination of hvip, and mip for vs-mode.
+ *
+ * Both report bits 2, 6, 10 and 13:63.
+ * vsip needs to be read-only zero when both hideleg[i] and
+ * hvien[i] are zero.
+ */
static RISCVException rmw_hvip64(CPURISCVState *env, int csrno,
uint64_t *ret_val,
uint64_t new_val, uint64_t wr_mask)
{
RISCVException ret;
+ uint64_t old_hvip;
+ uint64_t ret_mip;
+
+ /*
+ * For bits 10, 6 and 2, vsip[i] is an alias of hip[i]. These bits are
+ * present in hip, hvip and mip. Where mip[i] is alias of hip[i] and
hvip[i]
+ * is OR'ed in hip[i] to inject virtual interrupts from hypervisor. These
+ * bits are actually being maintained in mip so we read them from there.
+ * This way we have a single source of truth and allows for easier
+ * implementation.
+ *
+ * For bits 13:63 we have:
+ *
+ * hideleg[i] hvien[i]
+ * 0 0 No delegation. vsip[i] readonly zero.
+ * 0 1 vsip[i] is alias of hvip[i], sip bypassed.
+ * 1 X vsip[i] is alias of sip[i], hvip bypassed.
+ *
+ * alias_mask denotes the bits that come from sip (mip here given we
+ * maintain all bits there). nalias_mask denotes bits that come from
+ * hvip.
+ */
+ uint64_t alias_mask = (env->hideleg | ~env->hvien) | VS_MODE_INTERRUPTS;
+ uint64_t nalias_mask = (~env->hideleg & env->hvien);
+ uint64_t wr_mask_hvip;
+ uint64_t wr_mask_mip;
+
+ /*
+ * Both alias and non-alias mask remain same for vsip except:
+ * 1- For VS* bits if they are zero in hideleg.
+ * 2- For 13:63 bits if they are zero in both hideleg and hvien.
+ */
+ if (csrno == CSR_VSIP) {
+ /* zero-out VS* bits that are not delegated to VS mode. */
+ alias_mask &= (env->hideleg | ~VS_MODE_INTERRUPTS);
+
+ /*
+ * zero-out 13:63 bits that are zero in both hideleg and hvien.
+ * nalias_mask mask can not contain any VS* bits so only second
+ * condition applies on it.
+ */
+ nalias_mask &= (env->hideleg | env->hvien);
+ alias_mask &= (env->hideleg | env->hvien);
+ }
+
+ wr_mask_hvip = wr_mask & nalias_mask & hvip_writable_mask;
+ wr_mask_mip = wr_mask & alias_mask & hvip_writable_mask;
+
+ /* Aliased bits, bits 10, 6, 2 need to come from mip. */
+ ret = rmw_mip64(env, csrno, &ret_mip, new_val, wr_mask_mip);
+ if (ret != RISCV_EXCP_NONE) {
+ return ret;
+ }
+
+ old_hvip = env->hvip;
+
+ if (wr_mask_hvip) {
+ env->hvip = (env->hvip & ~wr_mask_hvip) | (new_val & wr_mask_hvip);
+
+ /*
+ * Given hvip is separate source from mip, we need to trigger interrupt
+ * from here separately. Normally this happen from
riscv_cpu_update_mip.
+ */
+ riscv_cpu_interrupt(env);
+ }
- ret = rmw_mip64(env, csrno, ret_val, new_val,
- wr_mask & hvip_writable_mask);
if (ret_val) {
- *ret_val &= VS_MODE_INTERRUPTS;
+ /* Only take VS* bits from mip. */
+ ret_mip &= alias_mask;
+
+ /* Take in non-delegated 13:63 bits from hvip. */
+ old_hvip &= nalias_mask;
+
+ *ret_val = ret_mip | old_hvip;
}
return ret;
@@ -4527,14 +4689,13 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
.min_priv_ver = PRIV_VERSION_1_12_0
},
/* Virtual Interrupts and Interrupt Priorities (H-extension with AIA) */
- [CSR_HVIEN] = { "hvien", aia_hmode, read_zero, write_ignore },
+ [CSR_HVIEN] = { "hvien", aia_hmode, NULL, NULL, rmw_hvien },
[CSR_HVICTL] = { "hvictl", aia_hmode, read_hvictl,
write_hvictl },
[CSR_HVIPRIO1] = { "hviprio1", aia_hmode, read_hviprio1,
write_hviprio1 },
[CSR_HVIPRIO2] = { "hviprio2", aia_hmode, read_hviprio2,
write_hviprio2 },
-
/*
* VS-Level Window to Indirectly Accessed Registers (H-extension with AIA)
*/
@@ -4549,8 +4710,7 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
/* Hypervisor and VS-Level High-Half CSRs (H-extension with AIA) */
[CSR_HIDELEGH] = { "hidelegh", aia_hmode32, NULL, NULL,
rmw_hidelegh },
- [CSR_HVIENH] = { "hvienh", aia_hmode32, read_zero,
- write_ignore },
+ [CSR_HVIENH] = { "hvienh", aia_hmode32, NULL, NULL, rmw_hvienh },
[CSR_HVIPH] = { "hviph", aia_hmode32, NULL, NULL, rmw_hviph },
[CSR_HVIPRIO1H] = { "hviprio1h", aia_hmode32, read_hviprio1h,
write_hviprio1h },
diff --git a/target/riscv/machine.c b/target/riscv/machine.c
index dd7bdbb691..3fff230a1c 100644
--- a/target/riscv/machine.c
+++ b/target/riscv/machine.c
@@ -92,6 +92,8 @@ static const VMStateDescription vmstate_hyper = {
VMSTATE_UINTTL(env.hgatp, RISCVCPU),
VMSTATE_UINTTL(env.hgeie, RISCVCPU),
VMSTATE_UINTTL(env.hgeip, RISCVCPU),
+ VMSTATE_UINT64(env.hvien, RISCVCPU),
+ VMSTATE_UINT64(env.hvip, RISCVCPU),
VMSTATE_UINT64(env.htimedelta, RISCVCPU),
VMSTATE_UINT64(env.vstimecmp, RISCVCPU),
@@ -106,6 +108,7 @@ static const VMStateDescription vmstate_hyper = {
VMSTATE_UINTTL(env.vstval, RISCVCPU),
VMSTATE_UINTTL(env.vsatp, RISCVCPU),
VMSTATE_UINTTL(env.vsiselect, RISCVCPU),
+ VMSTATE_UINT64(env.vsie, RISCVCPU),
VMSTATE_UINTTL(env.mtval2, RISCVCPU),
VMSTATE_UINTTL(env.mtinst, RISCVCPU),