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KVM: arm64: Use the xarray as the primary sysreg/sysinsn walker

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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.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-16-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Marc Zyngier
2024-02-14 13:18:16 +00:00
committed by Oliver Upton
parent 19f3e7ea29
commit cc5f84fbb0
3 changed files with 50 additions and 55 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/arm64/include/asm/kvm_nested.h
+1 -1
View File
@@ -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);
arch/arm64/kvm/emulate-nested.c
+30 -10
View File
@@ -2007,7 +2007,7 @@ 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;
@@ -2015,9 +2015,6 @@ 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;
@@ -2028,13 +2025,16 @@ 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__:
@@ -2076,7 +2076,7 @@ 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,
@@ -2089,6 +2089,26 @@ bool __check_nv_sr_forward(struct kvm_vcpu *vcpu)
((b & BEHAVE_FORWARD_WRITE) && !is_read))
goto inject;
local:
if (!tc.sri) {
struct sys_reg_params params;
params = esr_sys64_to_params(esr);
/*
* Check for the IMPDEF range, as per DDI0487 J.a,
* D18.3.2 Reserved encodings for IMPLEMENTATION
* DEFINED registers.
*/
if (!(params.Op0 == 3 && (params.CRn & 0b1011) == 0b1011))
print_sys_reg_msg(&params,
"Unsupported guest access at: %lx\n",
*vcpu_pc(vcpu));
kvm_inject_undefined(vcpu);
return true;
}
*sr_index = tc.sri - 1;
return false;
inject:
arch/arm64/kvm/sys_regs.c
+19 -44
View File
@@ -3395,12 +3395,6 @@ int kvm_handle_cp14_32(struct kvm_vcpu *vcpu)
return kvm_handle_cp_32(vcpu, &params, 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
@@ -3409,46 +3403,24 @@ 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);
}
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));
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;
}
static void kvm_reset_id_regs(struct kvm_vcpu *vcpu)
{
const struct sys_reg_desc *idreg = first_idreg;
@@ -3502,31 +3474,34 @@ 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 registers have Op0=={2,3}, as per DDI487 J.a C5.1.2 */
if (params.Op0 == 2 || params.Op0 == 3) {
if (!emulate_sys_reg(vcpu, &params))
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, &params, 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, &params);
return 1;
}
/******************************************************************************