[RFC PATCH v3 1/6] lib: sbi: Preserve hypervisor and VS state across domain switches
Theodorus Wensan Februanto
theodoruswensanfebruanto025 at gmail.com
Wed Nov 4 20:43:34 PST 2026
Save outgoing VS state before modifying S/H interrupt configuration,
then restore incoming VS state after the H state exchange.
Preserve core H-extension CSRs, optional Smaia hypervisor interrupt
state, and Smstateen state-enable registers.
Include hvien, hvictl, hviprio1, hviprio2, and the RV32 VS interrupt
high-half CSRs.
Link: https://github.com/riscv-software-src/opensbi/issues/433
Signed-off-by: Theodorus Wensan Februanto <theodoruswensanfebruanto025 at gmail.com>
---
lib/sbi/sbi_domain_context.c | 112 +++++++++++++++++++++++++++++++++++
1 file changed, 112 insertions(+)
diff --git a/lib/sbi/sbi_domain_context.c b/lib/sbi/sbi_domain_context.c
index 987ac7fa..c34d4cbb 100644
--- a/lib/sbi/sbi_domain_context.c
+++ b/lib/sbi/sbi_domain_context.c
@@ -21,6 +21,42 @@
#include <sbi/sbi_vector.h>
#include <sbi/sbi_fp.h>
+struct hart_context_hext {
+ unsigned long hstatus;
+ unsigned long hedeleg;
+ unsigned long hideleg;
+ unsigned long hie;
+ unsigned long hgeie;
+ u64 henvcfg;
+ unsigned long htval;
+ unsigned long htinst;
+ unsigned long hvip;
+ unsigned long hgatp;
+ /** Optional hypervisor state */
+ u64 hvien;
+ unsigned long hvictl;
+ u64 hviprio1;
+ u64 hviprio2;
+ u64 hstateen[4];
+#if __riscv_xlen == 32
+ unsigned long hidelegh;
+ unsigned long hviph;
+ unsigned long vsieh;
+ unsigned long vsiph;
+#endif
+ unsigned long hcounteren;
+ u64 htimedelta;
+ unsigned long vsstatus;
+ unsigned long vsie;
+ unsigned long vstvec;
+ unsigned long vsscratch;
+ unsigned long vsepc;
+ unsigned long vscause;
+ unsigned long vstval;
+ unsigned long vsip;
+ unsigned long vsatp;
+};
+
/** Context representation for a hart within a domain */
struct hart_context {
/** Trap-related states such as GPRs, mepc, and mstatus */
@@ -44,6 +80,8 @@ struct hart_context {
unsigned long sip;
/** Supervisor address translation and protection register */
unsigned long satp;
+
+ struct hart_context_hext hext;
/** Counter-enable register */
unsigned long scounteren;
/** Supervisor environment configuration register */
@@ -131,6 +169,25 @@ static int switch_to_next_domain_context(struct hart_context *ctx,
sbi_hartmask_set_hartindex(hartindex, &target_dom->assigned_harts);
spin_unlock(&target_dom->assigned_harts_lock);
+ /* Save outgoing VS state before modifying S/H interrupt CSRs. */
+ if (misa_extension('H')) {
+ ctx->hext.vsstatus = csr_read(CSR_VSSTATUS);
+ ctx->hext.vsie = csr_read(CSR_VSIE);
+ ctx->hext.vstvec = csr_read(CSR_VSTVEC);
+ ctx->hext.vsscratch = csr_read(CSR_VSSCRATCH);
+ ctx->hext.vsepc = csr_read(CSR_VSEPC);
+ ctx->hext.vscause = csr_read(CSR_VSCAUSE);
+ ctx->hext.vstval = csr_read(CSR_VSTVAL);
+ ctx->hext.vsip = csr_read(CSR_VSIP);
+ ctx->hext.vsatp = csr_read(CSR_VSATP);
+#if __riscv_xlen == 32
+ if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SMAIA)) {
+ ctx->hext.vsieh = csr_read(CSR_VSIEH);
+ ctx->hext.vsiph = csr_read(CSR_VSIPH);
+ }
+#endif
+ }
+
/* Save current CSR context and restore target domain's CSR context */
ctx->sstatus = csr_swap(CSR_SSTATUS, dom_ctx->sstatus);
ctx->sie = csr_swap(CSR_SIE, dom_ctx->sie);
@@ -141,6 +198,61 @@ static int switch_to_next_domain_context(struct hart_context *ctx,
ctx->stval = csr_swap(CSR_STVAL, dom_ctx->stval);
ctx->sip = csr_swap(CSR_SIP, dom_ctx->sip);
ctx->satp = csr_swap(CSR_SATP, dom_ctx->satp);
+
+ if (misa_extension('H')) {
+ ctx->hext.hstatus = csr_swap(CSR_HSTATUS, dom_ctx->hext.hstatus);
+ ctx->hext.hedeleg = csr_swap(CSR_HEDELEG, dom_ctx->hext.hedeleg);
+ ctx->hext.hideleg = csr_swap(CSR_HIDELEG, dom_ctx->hext.hideleg);
+ ctx->hext.hie = csr_swap(CSR_HIE, dom_ctx->hext.hie);
+ ctx->hext.hgeie = csr_swap(CSR_HGEIE, dom_ctx->hext.hgeie);
+ ctx->hext.henvcfg = csr_swap64(CSR_HENVCFG, dom_ctx->hext.henvcfg);
+ ctx->hext.htval = csr_swap(CSR_HTVAL, dom_ctx->hext.htval);
+ ctx->hext.htinst = csr_swap(CSR_HTINST, dom_ctx->hext.htinst);
+ ctx->hext.hvip = csr_swap(CSR_HVIP, dom_ctx->hext.hvip);
+ ctx->hext.hgatp = csr_swap(CSR_HGATP, dom_ctx->hext.hgatp);
+ ctx->hext.hcounteren = csr_swap(CSR_HCOUNTEREN, dom_ctx->hext.hcounteren);
+ ctx->hext.htimedelta = csr_swap64(CSR_HTIMEDELTA, dom_ctx->hext.htimedelta);
+#if __riscv_xlen == 32
+ if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SMAIA)) {
+ ctx->hext.hidelegh = csr_swap(CSR_HIDELEGH,
+ dom_ctx->hext.hidelegh);
+ ctx->hext.hviph = csr_swap(CSR_HVIPH, dom_ctx->hext.hviph);
+ }
+#endif
+ if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SMAIA)) {
+ ctx->hext.hvien = csr_swap64(CSR_HVIEN, dom_ctx->hext.hvien);
+ ctx->hext.hvictl = csr_swap(CSR_HVICTL, dom_ctx->hext.hvictl);
+ ctx->hext.hviprio1 = csr_swap64(CSR_HVIPRIO1, dom_ctx->hext.hviprio1);
+ ctx->hext.hviprio2 = csr_swap64(CSR_HVIPRIO2, dom_ctx->hext.hviprio2);
+ }
+
+ if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SMSTATEEN)) {
+ ctx->hext.hstateen[0] = csr_swap64(CSR_HSTATEEN0,
+ dom_ctx->hext.hstateen[0]);
+ ctx->hext.hstateen[1] = csr_swap64(CSR_HSTATEEN1,
+ dom_ctx->hext.hstateen[1]);
+ ctx->hext.hstateen[2] = csr_swap64(CSR_HSTATEEN2,
+ dom_ctx->hext.hstateen[2]);
+ ctx->hext.hstateen[3] = csr_swap64(CSR_HSTATEEN3,
+ dom_ctx->hext.hstateen[3]);
+ }
+ /* Restore incoming VS state after H interrupt configuration. */
+ csr_write(CSR_VSSTATUS, dom_ctx->hext.vsstatus);
+ csr_write(CSR_VSIE, dom_ctx->hext.vsie);
+ csr_write(CSR_VSTVEC, dom_ctx->hext.vstvec);
+ csr_write(CSR_VSSCRATCH, dom_ctx->hext.vsscratch);
+ csr_write(CSR_VSEPC, dom_ctx->hext.vsepc);
+ csr_write(CSR_VSCAUSE, dom_ctx->hext.vscause);
+ csr_write(CSR_VSTVAL, dom_ctx->hext.vstval);
+ csr_write(CSR_VSIP, dom_ctx->hext.vsip);
+ csr_write(CSR_VSATP, dom_ctx->hext.vsatp);
+#if __riscv_xlen == 32
+ if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SMAIA)) {
+ csr_write(CSR_VSIEH, dom_ctx->hext.vsieh);
+ csr_write(CSR_VSIPH, dom_ctx->hext.vsiph);
+ }
+#endif
+ }
if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_10)
ctx->scounteren = csr_swap(CSR_SCOUNTEREN, dom_ctx->scounteren);
if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_12)
--
2.43.0
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