In preparation for CTR_EL0 emulation maintain a per VM for this
register and use it where appropriate.
Signed-off-by: Sebastian Ott <sebott@redhat.com>
---
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++-------
2 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 9e8a496fb284..481216febb46 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -318,6 +318,7 @@ struct kvm_arch {
/* PMCR_EL0.N value for the guest */
u8 pmcr_n;
+ u64 ctr_el0;
/* Iterator for idreg debugfs */
u8 idreg_debugfs_iter;
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 131f5b0ca2b9..4d29b1a0842d 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -215,13 +215,21 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
#define CSSELR_MAX 14
+static u64 kvm_get_ctr_el0(struct kvm *kvm)
+{
+ if (kvm->arch.ctr_el0)
+ return kvm->arch.ctr_el0;
+
+ return read_sanitised_ftr_reg(SYS_CTR_EL0);
+}
+
/*
* Returns the minimum line size for the selected cache, expressed as
* Log2(bytes).
*/
-static u8 get_min_cache_line_size(bool icache)
+static u8 get_min_cache_line_size(struct kvm *kvm, bool icache)
{
- u64 ctr = read_sanitised_ftr_reg(SYS_CTR_EL0);
+ u64 ctr = kvm_get_ctr_el0(kvm);
u8 field;
if (icache)
@@ -248,7 +256,7 @@ static u32 get_ccsidr(struct kvm_vcpu *vcpu, u32 csselr)
if (vcpu->arch.ccsidr)
return vcpu->arch.ccsidr[csselr];
- line_size = get_min_cache_line_size(csselr & CSSELR_EL1_InD);
+ line_size = get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD);
/*
* Fabricate a CCSIDR value as the overriding value does not exist.
@@ -283,7 +291,7 @@ static int set_ccsidr(struct kvm_vcpu *vcpu, u32 csselr, u32 val)
u32 i;
if ((val & CCSIDR_EL1_RES0) ||
- line_size < get_min_cache_line_size(csselr & CSSELR_EL1_InD))
+ line_size < get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD))
return -EINVAL;
if (!ccsidr) {
@@ -1862,7 +1870,7 @@ static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
if (p->is_write)
return write_to_read_only(vcpu, p, r);
- p->regval = read_sanitised_ftr_reg(SYS_CTR_EL0);
+ p->regval = kvm_get_ctr_el0(vcpu->kvm);
return true;
}
@@ -1882,7 +1890,7 @@ static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
*/
static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
- u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
+ u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm);
u64 clidr;
u8 loc;
@@ -1935,7 +1943,7 @@ static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
static int set_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
u64 val)
{
- u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
+ u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm);
u64 idc = !CLIDR_LOC(val) || (!CLIDR_LOUIS(val) && !CLIDR_LOUU(val));
if ((val & CLIDR_EL1_RES0) || (!(ctr_el0 & CTR_EL0_IDC) && idc))
--
2.42.0On Fri, 05 Apr 2024 13:01:06 +0100,
Sebastian Ott <sebott@redhat.com> wrote:
>
> In preparation for CTR_EL0 emulation maintain a per VM for this
> register and use it where appropriate.
>
> Signed-off-by: Sebastian Ott <sebott@redhat.com>
> ---
> arch/arm64/include/asm/kvm_host.h | 1 +
> arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++-------
> 2 files changed, 16 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 9e8a496fb284..481216febb46 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -318,6 +318,7 @@ struct kvm_arch {
>
> /* PMCR_EL0.N value for the guest */
> u8 pmcr_n;
> + u64 ctr_el0;
>
> /* Iterator for idreg debugfs */
> u8 idreg_debugfs_iter;
Please consider the alignment of the fields. This leaves a 7 byte hole
that could be avoided (yes, I'm on a mission to reduce the size of the
various structures, because they are absolute pigs).
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 131f5b0ca2b9..4d29b1a0842d 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -215,13 +215,21 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
> /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
> #define CSSELR_MAX 14
>
> +static u64 kvm_get_ctr_el0(struct kvm *kvm)
> +{
> + if (kvm->arch.ctr_el0)
> + return kvm->arch.ctr_el0;
Is this relying on some bits not being 0?
> +
> + return read_sanitised_ftr_reg(SYS_CTR_EL0);
Why isn't the shadow value always populated?
> +}
> +
> /*
> * Returns the minimum line size for the selected cache, expressed as
> * Log2(bytes).
> */
> -static u8 get_min_cache_line_size(bool icache)
> +static u8 get_min_cache_line_size(struct kvm *kvm, bool icache)
> {
> - u64 ctr = read_sanitised_ftr_reg(SYS_CTR_EL0);
> + u64 ctr = kvm_get_ctr_el0(kvm);
> u8 field;
>
> if (icache)
> @@ -248,7 +256,7 @@ static u32 get_ccsidr(struct kvm_vcpu *vcpu, u32 csselr)
> if (vcpu->arch.ccsidr)
> return vcpu->arch.ccsidr[csselr];
>
> - line_size = get_min_cache_line_size(csselr & CSSELR_EL1_InD);
> + line_size = get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD);
>
> /*
> * Fabricate a CCSIDR value as the overriding value does not exist.
> @@ -283,7 +291,7 @@ static int set_ccsidr(struct kvm_vcpu *vcpu, u32 csselr, u32 val)
> u32 i;
>
> if ((val & CCSIDR_EL1_RES0) ||
> - line_size < get_min_cache_line_size(csselr & CSSELR_EL1_InD))
> + line_size < get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD))
> return -EINVAL;
>
> if (!ccsidr) {
> @@ -1862,7 +1870,7 @@ static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> if (p->is_write)
> return write_to_read_only(vcpu, p, r);
>
> - p->regval = read_sanitised_ftr_reg(SYS_CTR_EL0);
> + p->regval = kvm_get_ctr_el0(vcpu->kvm);
> return true;
> }
>
> @@ -1882,7 +1890,7 @@ static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> */
> static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> - u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
> + u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm);
> u64 clidr;
> u8 loc;
>
> @@ -1935,7 +1943,7 @@ static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> static int set_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> u64 val)
> {
> - u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
> + u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm);
> u64 idc = !CLIDR_LOC(val) || (!CLIDR_LOUIS(val) && !CLIDR_LOUU(val));
>
> if ((val & CLIDR_EL1_RES0) || (!(ctr_el0 & CTR_EL0_IDC) && idc))
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
On Sat, 13 Apr 2024, Marc Zyngier wrote:
> On Fri, 05 Apr 2024 13:01:06 +0100,
> Sebastian Ott <sebott@redhat.com> wrote:
>>
>> In preparation for CTR_EL0 emulation maintain a per VM for this
>> register and use it where appropriate.
>>
>> Signed-off-by: Sebastian Ott <sebott@redhat.com>
>> ---
>> arch/arm64/include/asm/kvm_host.h | 1 +
>> arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++-------
>> 2 files changed, 16 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
>> index 9e8a496fb284..481216febb46 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -318,6 +318,7 @@ struct kvm_arch {
>>
>> /* PMCR_EL0.N value for the guest */
>> u8 pmcr_n;
>> + u64 ctr_el0;
>>
>> /* Iterator for idreg debugfs */
>> u8 idreg_debugfs_iter;
>
> Please consider the alignment of the fields. This leaves a 7 byte hole
> that could be avoided (yes, I'm on a mission to reduce the size of the
> various structures, because they are absolute pigs).
OK.
>> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
>> index 131f5b0ca2b9..4d29b1a0842d 100644
>> --- a/arch/arm64/kvm/sys_regs.c
>> +++ b/arch/arm64/kvm/sys_regs.c
>> @@ -215,13 +215,21 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
>> /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
>> #define CSSELR_MAX 14
>>
>> +static u64 kvm_get_ctr_el0(struct kvm *kvm)
>> +{
>> + if (kvm->arch.ctr_el0)
>> + return kvm->arch.ctr_el0;
>
> Is this relying on some bits not being 0?
>
>> +
>> + return read_sanitised_ftr_reg(SYS_CTR_EL0);
>
> Why isn't the shadow value always populated?
The idea was for kvm->arch.ctr_el0 being non zero only if userspace
set it up to differ from the host value. So it can be used to decide
if we need to set up a trap for the reg access (without comparing it
to the host value again).
Thanks,
Sebastian
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