[PATCH 15/25] KVM: arm64: Use the xarray as the primary sysreg/sysinsn walker
Marc Zyngier
maz at kernel.org
Mon Jan 22 12:18:42 PST 2024
Since we always start sysreg/sysinsn handling by searching the
xarray, use it as the source of the index in the correct sys_reg_desc
array.
This allows some cleanup, such as moving the handling of unknown
sysregs in a single location.
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
arch/arm64/include/asm/kvm_nested.h | 2 +-
arch/arm64/kvm/emulate-nested.c | 36 +++++++++++-----
arch/arm64/kvm/sys_regs.c | 64 +++++++++--------------------
3 files changed, 46 insertions(+), 56 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index 4882905357f4..68465f87d308 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -60,7 +60,7 @@ static inline u64 translate_ttbr0_el2_to_ttbr0_el1(u64 ttbr0)
return ttbr0 & ~GENMASK_ULL(63, 48);
}
-extern bool __check_nv_sr_forward(struct kvm_vcpu *vcpu);
+extern bool __check_nv_sr_forward(struct kvm_vcpu *vcpu, int *sr_idx);
int kvm_init_nv_sysregs(struct kvm *kvm);
diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 342d43b66fda..54ab4d240fc6 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -2001,7 +2001,7 @@ static bool check_fgt_bit(struct kvm *kvm, bool is_read,
return !(kvm_get_sysreg_res0(kvm, sr) & BIT(tc.bit));
}
-bool __check_nv_sr_forward(struct kvm_vcpu *vcpu)
+bool __check_nv_sr_forward(struct kvm_vcpu *vcpu, int *sr_index)
{
union trap_config tc;
enum trap_behaviour b;
@@ -2009,9 +2009,6 @@ bool __check_nv_sr_forward(struct kvm_vcpu *vcpu)
u32 sysreg;
u64 esr, val;
- if (!vcpu_has_nv(vcpu) || is_hyp_ctxt(vcpu))
- return false;
-
esr = kvm_vcpu_get_esr(vcpu);
sysreg = esr_sys64_to_sysreg(esr);
is_read = (esr & ESR_ELx_SYS64_ISS_DIR_MASK) == ESR_ELx_SYS64_ISS_DIR_READ;
@@ -2022,13 +2019,16 @@ bool __check_nv_sr_forward(struct kvm_vcpu *vcpu)
* A value of 0 for the whole entry means that we know nothing
* for this sysreg, and that it cannot be re-injected into the
* nested hypervisor. In this situation, let's cut it short.
- *
- * Note that ultimately, we could also make use of the xarray
- * to store the index of the sysreg in the local descriptor
- * array, avoiding another search... Hint, hint...
*/
if (!tc.val)
- return false;
+ goto local;
+
+ /*
+ * If we're not nesting, immediately return to the caller, with the
+ * sysreg index, should we have it.
+ */
+ if (!vcpu_has_nv(vcpu) || is_hyp_ctxt(vcpu))
+ goto local;
switch ((enum fgt_group_id)tc.fgt) {
case __NO_FGT_GROUP__:
@@ -2070,7 +2070,7 @@ bool __check_nv_sr_forward(struct kvm_vcpu *vcpu)
case __NR_FGT_GROUP_IDS__:
/* Something is really wrong, bail out */
WARN_ONCE(1, "__NR_FGT_GROUP_IDS__");
- return false;
+ goto local;
}
if (tc.fgt != __NO_FGT_GROUP__ && check_fgt_bit(vcpu->kvm, is_read,
@@ -2083,6 +2083,22 @@ bool __check_nv_sr_forward(struct kvm_vcpu *vcpu)
((b & BEHAVE_FORWARD_WRITE) && !is_read))
goto inject;
+local:
+ if (!tc.msr) {
+ struct sys_reg_params params;
+
+ params = esr_sys64_to_params(esr);
+
+ // IMPDEF range. See ARM DDI 0487E.a, section D12.3.2
+ if (!(params.Op0 == 3 && (params.CRn & 0b1011) == 0b1011))
+ print_sys_reg_msg(¶ms,
+ "Unsupported guest access at: %lx\n",
+ *vcpu_pc(vcpu));
+ kvm_inject_undefined(vcpu);
+ return true;
+ }
+
+ *sr_index = tc.msr - 1;
return false;
inject:
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 65319193e443..794d1f8c9bfe 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -3397,12 +3397,6 @@ int kvm_handle_cp14_32(struct kvm_vcpu *vcpu)
return kvm_handle_cp_32(vcpu, ¶ms, cp14_regs, ARRAY_SIZE(cp14_regs));
}
-static bool is_imp_def_sys_reg(struct sys_reg_params *params)
-{
- // See ARM DDI 0487E.a, section D12.3.2
- return params->Op0 == 3 && (params->CRn & 0b1011) == 0b1011;
-}
-
/**
* emulate_sys_reg - Emulate a guest access to an AArch64 system register
* @vcpu: The VCPU pointer
@@ -3411,44 +3405,22 @@ static bool is_imp_def_sys_reg(struct sys_reg_params *params)
* Return: true if the system register access was successful, false otherwise.
*/
static bool emulate_sys_reg(struct kvm_vcpu *vcpu,
- struct sys_reg_params *params)
+ struct sys_reg_params *params)
{
const struct sys_reg_desc *r;
r = find_reg(params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
-
if (likely(r)) {
perform_access(vcpu, params, r);
return true;
}
- if (is_imp_def_sys_reg(params)) {
- kvm_inject_undefined(vcpu);
- } else {
- print_sys_reg_msg(params,
- "Unsupported guest sys_reg access at: %lx [%08lx]\n",
- *vcpu_pc(vcpu), *vcpu_cpsr(vcpu));
- kvm_inject_undefined(vcpu);
- }
- return false;
-}
-
-static int emulate_sys_instr(struct kvm_vcpu *vcpu, struct sys_reg_params *p)
-{
- const struct sys_reg_desc *r;
-
- /* Search from the system instruction table. */
- r = find_reg(p, sys_insn_descs, ARRAY_SIZE(sys_insn_descs));
+ print_sys_reg_msg(params,
+ "Unsupported guest sys_reg access at: %lx [%08lx]\n",
+ *vcpu_pc(vcpu), *vcpu_cpsr(vcpu));
+ kvm_inject_undefined(vcpu);
- if (likely(r)) {
- perform_access(vcpu, p, r);
- } else {
- kvm_err("Unsupported guest sys instruction at: %lx\n",
- *vcpu_pc(vcpu));
- print_sys_reg_instr(p);
- kvm_inject_undefined(vcpu);
- }
- return 1;
+ return false;
}
static void kvm_reset_id_regs(struct kvm_vcpu *vcpu)
@@ -3504,31 +3476,33 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
*/
int kvm_handle_sys_reg(struct kvm_vcpu *vcpu)
{
+ const struct sys_reg_desc *desc = NULL;
struct sys_reg_params params;
unsigned long esr = kvm_vcpu_get_esr(vcpu);
int Rt = kvm_vcpu_sys_get_rt(vcpu);
+ int sr_idx;
trace_kvm_handle_sys_reg(esr);
- if (__check_nv_sr_forward(vcpu))
+ if (__check_nv_sr_forward(vcpu, &sr_idx))
return 1;
params = esr_sys64_to_params(esr);
params.regval = vcpu_get_reg(vcpu, Rt);
- /* System register? */
- if (params.Op0 == 2 || params.Op0 == 3) {
- if (!emulate_sys_reg(vcpu, ¶ms))
- return 1;
+ if (params.Op0 == 2 || params.Op0 == 3)
+ desc = &sys_reg_descs[sr_idx];
+ else
+ desc = &sys_insn_descs[sr_idx];
- if (!params.is_write)
- vcpu_set_reg(vcpu, Rt, params.regval);
+ perform_access(vcpu, ¶ms, desc);
- return 1;
- }
+ /* Read from system register? */
+ if (!params.is_write &&
+ (params.Op0 == 2 || params.Op0 == 3))
+ vcpu_set_reg(vcpu, Rt, params.regval);
- /* Hints, PSTATE (Op0 == 0) and System instructions (Op0 == 1) */
- return emulate_sys_instr(vcpu, ¶ms);
+ return 1;
}
/******************************************************************************
--
2.39.2
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