[PATCH v5 35/43] arm64: RME: Propagate number of breakpoints and watchpoints to userspace
From: Steven Price
Date: Fri Oct 04 2024 - 11:40:48 EST
From: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
The RMM describes the maximum number of BPs/WPs available to the guest
in the Feature Register 0. Propagate those numbers into ID_AA64DFR0_EL1,
which is visible to userspace. A VMM needs this information in order to
set up realm parameters.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
arch/arm64/include/asm/kvm_rme.h | 1 +
arch/arm64/kvm/rme.c | 22 ++++++++++++++++++++++
arch/arm64/kvm/sys_regs.c | 2 +-
3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index f3ef166e0755..2b454ad633a6 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -88,6 +88,7 @@ struct realm_rec {
void kvm_init_rme(void);
u32 kvm_realm_ipa_limit(void);
+u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val);
bool kvm_rme_supports_sve(void);
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 9a4d0299e56a..87f466e5b548 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -286,6 +286,28 @@ u32 kvm_realm_ipa_limit(void)
return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
}
+u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val)
+{
+ u32 bps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_BPS);
+ u32 wps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_WPS);
+ u32 ctx_cmps;
+
+ if (!kvm_is_realm(vcpu->kvm))
+ return val;
+
+ /* Ensure CTX_CMPs is still valid */
+ ctx_cmps = FIELD_GET(ID_AA64DFR0_EL1_CTX_CMPs, val);
+ ctx_cmps = min(bps, ctx_cmps);
+
+ val &= ~(ID_AA64DFR0_EL1_BRPs_MASK | ID_AA64DFR0_EL1_WRPs_MASK |
+ ID_AA64DFR0_EL1_CTX_CMPs);
+ val |= FIELD_PREP(ID_AA64DFR0_EL1_BRPs_MASK, bps) |
+ FIELD_PREP(ID_AA64DFR0_EL1_WRPs_MASK, wps) |
+ FIELD_PREP(ID_AA64DFR0_EL1_CTX_CMPs, ctx_cmps);
+
+ return val;
+}
+
static int realm_create_rd(struct kvm *kvm)
{
struct realm *realm = &kvm->arch.realm;
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 10949f3318ed..a73e0eb5dd85 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1746,7 +1746,7 @@ static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
/* Hide SPE from guests */
val &= ~ID_AA64DFR0_EL1_PMSVer_MASK;
- return val;
+ return kvm_realm_reset_id_aa64dfr0_el1(vcpu, val);
}
static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
--
2.34.1