From: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
All hcalls from a secure VM go to the ultravisor from where they are
reflected into the HV. When we (HV) complete processing such hcalls,
we should return to the UV rather than to the guest kernel.
Have fast_guest_return check the kvm_arch.secure_guest field so that
even a new CPU will enter UV when started (in response to a RTAS
start-cpu call).
Thanks to input from Paul Mackerras, Ram Pai and Mike Anderson.
Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
[Fix UV_RETURN token number and arch.secure_guest check]
Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
Signed-off-by: Claudio Carvalho <cclaudio@xxxxxxxxxxxxx>
---
arch/powerpc/include/asm/kvm_host.h | 1 +
arch/powerpc/include/asm/ultravisor-api.h | 1 +
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 30 ++++++++++++++++++++---
4 files changed, 29 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index e6b5bb012ccb..ba7dd35cb916 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -290,6 +290,7 @@ struct kvm_arch {
cpumask_t cpu_in_guest;
u8 radix;
u8 fwnmi_enabled;
+ u8 secure_guest;
bool threads_indep;
bool nested_enable;
pgd_t *pgtable;
diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
index 24bfb4c1737e..15e6ce77a131 100644
--- a/arch/powerpc/include/asm/ultravisor-api.h
+++ b/arch/powerpc/include/asm/ultravisor-api.h
@@ -19,5 +19,6 @@
/* opcodes */
#define UV_WRITE_PATE 0xF104
+#define UV_RETURN 0xF11C
#endif /* _ASM_POWERPC_ULTRAVISOR_API_H */
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 8e02444e9d3d..44742724513e 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -508,6 +508,7 @@ int main(void)
OFFSET(KVM_VRMA_SLB_V, kvm, arch.vrma_slb_v);
OFFSET(KVM_RADIX, kvm, arch.radix);
OFFSET(KVM_FWNMI, kvm, arch.fwnmi_enabled);
+ OFFSET(KVM_SECURE_GUEST, kvm, arch.secure_guest);
OFFSET(VCPU_DSISR, kvm_vcpu, arch.shregs.dsisr);
OFFSET(VCPU_DAR, kvm_vcpu, arch.shregs.dar);
OFFSET(VCPU_VPA, kvm_vcpu, arch.vpa.pinned_addr);
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 938cfa5dceed..d89efa0783a2 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -36,6 +36,7 @@
#include <asm/asm-compat.h>
#include <asm/feature-fixups.h>
#include <asm/cpuidle.h>
+#include <asm/ultravisor-api.h>
/* Sign-extend HDEC if not on POWER9 */
#define EXTEND_HDEC(reg) \
@@ -1112,16 +1113,12 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ld r5, VCPU_LR(r4)
- ld r6, VCPU_CR(r4)
mtlr r5
- mtcr r6
ld r1, VCPU_GPR(R1)(r4)
ld r2, VCPU_GPR(R2)(r4)
ld r3, VCPU_GPR(R3)(r4)
ld r5, VCPU_GPR(R5)(r4)
- ld r6, VCPU_GPR(R6)(r4)
- ld r7, VCPU_GPR(R7)(r4)
ld r8, VCPU_GPR(R8)(r4)
ld r9, VCPU_GPR(R9)(r4)
ld r10, VCPU_GPR(R10)(r4)
@@ -1139,10 +1136,35 @@ BEGIN_FTR_SECTION
mtspr SPRN_HDSISR, r0
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
+ ld r6, VCPU_KVM(r4)
+ lbz r7, KVM_SECURE_GUEST(r6)
+ cmpdi r7, 0
+ bne ret_to_ultra
+
+ lwz r6, VCPU_CR(r4)
+ mtcr r6
+
+ ld r7, VCPU_GPR(R7)(r4)
+ ld r6, VCPU_GPR(R6)(r4)
ld r0, VCPU_GPR(R0)(r4)
ld r4, VCPU_GPR(R4)(r4)
HRFI_TO_GUEST
b .
+/*
+ * The hcall we just completed was from Ultravisor. Use UV_RETURN
+ * ultra call to return to the Ultravisor. Results from the hcall
+ * are already in the appropriate registers (r3:12), except for
+ * R6,7 which we used as temporary registers above. Restore them,
+ * and set R0 to the ucall number (UV_RETURN).
+ */
+ret_to_ultra:
+ lwz r6, VCPU_CR(r4)
+ mtcr r6
+ LOAD_REG_IMMEDIATE(r0, UV_RETURN)
+ ld r7, VCPU_GPR(R7)(r4)
+ ld r6, VCPU_GPR(R6)(r4)
+ ld r4, VCPU_GPR(R4)(r4)
+ sc 2
/*
* Enter the guest on a P9 or later system where we have exactly
--
2.20.1
