[PATCH] arch/powerpc/kvm: Fix doorbell emulation by adding DPDES support
From: Gautam Menghani
Date: Wed May 22 2024 - 04:30:01 EST
Doorbell emulation is broken for KVM on PowerVM guests as support for
DPDES was not added in the initial patch series. Due to this, a KVM on
PowerVM guest cannot be booted with the XICS interrupt controller as
doorbells are to be setup in the initial probe path when using XICS
(pSeries_smp_probe()). Add DPDES support in the host KVM code to fix
doorbell emulation.
Fixes: 6ccbbc33f06a ("KVM: PPC: Add helper library for Guest State Buffers")
Signed-off-by: Gautam Menghani <gautam@xxxxxxxxxxxxx>
---
Documentation/arch/powerpc/kvm-nested.rst | 4 +++-
arch/powerpc/include/asm/guest-state-buffer.h | 3 ++-
arch/powerpc/include/asm/kvm_book3s.h | 1 +
arch/powerpc/kvm/book3s_hv.c | 14 +++++++++++++-
arch/powerpc/kvm/book3s_hv_nestedv2.c | 7 +++++++
arch/powerpc/kvm/test-guest-state-buffer.c | 2 +-
6 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/Documentation/arch/powerpc/kvm-nested.rst b/Documentation/arch/powerpc/kvm-nested.rst
index 630602a8aa00..5defd13cc6c1 100644
--- a/Documentation/arch/powerpc/kvm-nested.rst
+++ b/Documentation/arch/powerpc/kvm-nested.rst
@@ -546,7 +546,9 @@ table information.
+--------+-------+----+--------+----------------------------------+
| 0x1052 | 0x08 | RW | T | CTRL |
+--------+-------+----+--------+----------------------------------+
-| 0x1053-| | | | Reserved |
+| 0x1053 | 0x08 | RW | T | DPDES |
++--------+-------+----+--------+----------------------------------+
+| 0x1054-| | | | Reserved |
| 0x1FFF | | | | |
+--------+-------+----+--------+----------------------------------+
| 0x2000 | 0x04 | RW | T | CR |
diff --git a/arch/powerpc/include/asm/guest-state-buffer.h b/arch/powerpc/include/asm/guest-state-buffer.h
index 808149f31576..d107abe1468f 100644
--- a/arch/powerpc/include/asm/guest-state-buffer.h
+++ b/arch/powerpc/include/asm/guest-state-buffer.h
@@ -81,6 +81,7 @@
#define KVMPPC_GSID_HASHKEYR 0x1050
#define KVMPPC_GSID_HASHPKEYR 0x1051
#define KVMPPC_GSID_CTRL 0x1052
+#define KVMPPC_GSID_DPDES 0x1053
#define KVMPPC_GSID_CR 0x2000
#define KVMPPC_GSID_PIDR 0x2001
@@ -110,7 +111,7 @@
#define KVMPPC_GSE_META_COUNT (KVMPPC_GSE_META_END - KVMPPC_GSE_META_START + 1)
#define KVMPPC_GSE_DW_REGS_START KVMPPC_GSID_GPR(0)
-#define KVMPPC_GSE_DW_REGS_END KVMPPC_GSID_CTRL
+#define KVMPPC_GSE_DW_REGS_END KVMPPC_GSID_DPDES
#define KVMPPC_GSE_DW_REGS_COUNT \
(KVMPPC_GSE_DW_REGS_END - KVMPPC_GSE_DW_REGS_START + 1)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 3e1e2a698c9e..10618622d7ef 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -594,6 +594,7 @@ static inline u##size kvmppc_get_##reg(struct kvm_vcpu *vcpu) \
KVMPPC_BOOK3S_VCORE_ACCESSOR(vtb, 64, KVMPPC_GSID_VTB)
+KVMPPC_BOOK3S_VCORE_ACCESSOR(dpdes, 64, KVMPPC_GSID_DPDES)
KVMPPC_BOOK3S_VCORE_ACCESSOR_GET(arch_compat, 32, KVMPPC_GSID_LOGICAL_PVR)
KVMPPC_BOOK3S_VCORE_ACCESSOR_GET(lpcr, 64, KVMPPC_GSID_LPCR)
KVMPPC_BOOK3S_VCORE_ACCESSOR_SET(tb_offset, 64, KVMPPC_GSID_TB_OFFSET)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 35cb014a0c51..cf285e5153ba 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4116,6 +4116,11 @@ static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit,
int trap;
long rc;
+ if (vcpu->arch.doorbell_request) {
+ vcpu->arch.doorbell_request = 0;
+ kvmppc_set_dpdes(vcpu, 1);
+ }
+
io = &vcpu->arch.nestedv2_io;
msr = mfmsr();
@@ -4278,9 +4283,16 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
if (kvmhv_on_pseries()) {
if (kvmhv_is_nestedv1())
trap = kvmhv_vcpu_entry_p9_nested(vcpu, time_limit, lpcr, tb);
- else
+ else {
trap = kvmhv_vcpu_entry_nestedv2(vcpu, time_limit, lpcr, tb);
+ /* Remember doorbell if it is pending */
+ if (kvmppc_get_dpdes(vcpu)) {
+ vcpu->arch.doorbell_request = 1;
+ kvmppc_set_dpdes(vcpu, 0);
+ }
+ }
+
/* H_CEDE has to be handled now, not later */
if (trap == BOOK3S_INTERRUPT_SYSCALL && !nested &&
kvmppc_get_gpr(vcpu, 3) == H_CEDE) {
diff --git a/arch/powerpc/kvm/book3s_hv_nestedv2.c b/arch/powerpc/kvm/book3s_hv_nestedv2.c
index 8e6f5355f08b..36863fff2a99 100644
--- a/arch/powerpc/kvm/book3s_hv_nestedv2.c
+++ b/arch/powerpc/kvm/book3s_hv_nestedv2.c
@@ -311,6 +311,10 @@ static int gs_msg_ops_vcpu_fill_info(struct kvmppc_gs_buff *gsb,
rc = kvmppc_gse_put_u64(gsb, iden,
vcpu->arch.vcore->vtb);
break;
+ case KVMPPC_GSID_DPDES:
+ rc = kvmppc_gse_put_u64(gsb, iden,
+ vcpu->arch.vcore->dpdes);
+ break;
case KVMPPC_GSID_LPCR:
rc = kvmppc_gse_put_u64(gsb, iden,
vcpu->arch.vcore->lpcr);
@@ -543,6 +547,9 @@ static int gs_msg_ops_vcpu_refresh_info(struct kvmppc_gs_msg *gsm,
case KVMPPC_GSID_VTB:
vcpu->arch.vcore->vtb = kvmppc_gse_get_u64(gse);
break;
+ case KVMPPC_GSID_DPDES:
+ vcpu->arch.vcore->dpdes = kvmppc_gse_get_u64(gse);
+ break;
case KVMPPC_GSID_LPCR:
vcpu->arch.vcore->lpcr = kvmppc_gse_get_u64(gse);
break;
diff --git a/arch/powerpc/kvm/test-guest-state-buffer.c b/arch/powerpc/kvm/test-guest-state-buffer.c
index 4720b8dc8837..91ae660cfe21 100644
--- a/arch/powerpc/kvm/test-guest-state-buffer.c
+++ b/arch/powerpc/kvm/test-guest-state-buffer.c
@@ -151,7 +151,7 @@ static void test_gs_bitmap(struct kunit *test)
i++;
}
- for (u16 iden = KVMPPC_GSID_GPR(0); iden <= KVMPPC_GSID_CTRL; iden++) {
+ for (u16 iden = KVMPPC_GSID_GPR(0); iden <= KVMPPC_GSID_DPDES; iden++) {
kvmppc_gsbm_set(&gsbm, iden);
kvmppc_gsbm_set(&gsbm1, iden);
KUNIT_EXPECT_TRUE(test, kvmppc_gsbm_test(&gsbm, iden));
--
2.45.0