Re: [PATCH 3/3] KVM: arm64: Add emulation for 32bit guests accessing ACTLR2
From: Marc Zyngier <maz@kernel.org>
Date: 2020-05-28 12:51:41
Also in:
kvmarm
Hi James, On 2020-05-26 17:18, James Morse wrote:
quoted hunk ↗ jump to hunk
ACTLR_EL1 is a 64bit register while the 32bit ACTLR is obviously 32bit. For 32bit software, the extra bits are accessible via ACTLR2... which KVM doesn't emulate. Signed-off-by: James Morse <james.morse@arm.com> --- I'm not convinced this is endian safe, but it does match what kvm_inject_undef32() do. The alternative would be to always read the 64bit value, and generate the 32bit offets like access_vm_reg() does. arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/sys_regs_generic_v8.c | 16 +++++++++++++++- 2 files changed, 16 insertions(+), 1 deletion(-)diff --git a/arch/arm64/include/asm/kvm_host.hb/arch/arm64/include/asm/kvm_host.h index 32c8a675e5a4..5b7538663a8e 100644--- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h@@ -185,6 +185,7 @@ enum vcpu_sysreg { #define c0_CSSELR (CSSELR_EL1 * 2)/* Cache Size Selection Register */ #define c1_SCTLR (SCTLR_EL1 * 2) /* System Control Register */ #define c1_ACTLR (ACTLR_EL1 * 2) /* Auxiliary Control Register */ +#define c1_ACTLR2 (c1_ACTLR + 1) /* ACTLR top 32 bits */ #define c1_CPACR (CPACR_EL1 * 2) /* Coprocessor Access Control */ #define c2_TTBR0 (TTBR0_EL1 * 2) /* Translation Table Base Register 0*/ #define c2_TTBR0_high (c2_TTBR0 + 1) /* TTBR0 top 32 bits */diff --git a/arch/arm64/kvm/sys_regs_generic_v8.cb/arch/arm64/kvm/sys_regs_generic_v8.c index 9cb6b4c8355a..ed77bbb48e64 100644--- a/arch/arm64/kvm/sys_regs_generic_v8.c +++ b/arch/arm64/kvm/sys_regs_generic_v8.c@@ -30,6 +30,18 @@ static bool access_actlr(struct kvm_vcpu *vcpu, return true; } +static bool access_cp15_actlr(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + if (p->is_write) + return ignore_write(vcpu, p); + + p->regval = vcpu_cp15(vcpu, r->reg); + return true; + +} + static void reset_actlr(struct kvm_vcpu *vcpu, const structsys_reg_desc *r) { __vcpu_sys_reg(vcpu, ACTLR_EL1) = read_sysreg(actlr_el1);@@ -46,7 +58,9 @@ static const struct sys_reg_desc genericv8_sys_regs[]= { static const struct sys_reg_desc genericv8_cp15_regs[] = { /* ACTLR */ { Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b001), - access_actlr }, + access_cp15_actlr, NULL, c1_ACTLR }, + { Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b011), + access_cp15_actlr, NULL, c1_ACTLR2 }, }; static struct kvm_sys_reg_target_table genericv8_target_table = {
I'd get rid of any form of storage, and go with something like (untested, again):
diff --git a/arch/arm64/kvm/sys_regs_generic_v8.c b/arch/arm64/kvm/sys_regs_generic_v8.c index 9cb6b4c8355a..1b2bf2d37612 100644
--- a/arch/arm64/kvm/sys_regs_generic_v8.c
+++ b/arch/arm64/kvm/sys_regs_generic_v8.c@@ -26,13 +26,16 @@ static bool access_actlr(struct kvm_vcpu *vcpu, if (p->is_write) return ignore_write(vcpu, p); - p->regval = vcpu_read_sys_reg(vcpu, ACTLR_EL1); - return true; -} + p->regval = read_sysreg(actlr_el1); -static void reset_actlr(struct kvm_vcpu *vcpu, const struct
sys_reg_desc *r)
-{
- __vcpu_sys_reg(vcpu, ACTLR_EL1) = read_sysreg(actlr_el1);
+ if (p->aarch32) {
+ if (r->Op2 & 2)
+ p->regval = upper_32_bit(p->regval);
+ else
+ p->regval = lower_32_bit(p->regval);
+ }
+
+ return true;
}
/*@@ -40,13 +43,13 @@ static void reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
* Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
*/
static const struct sys_reg_desc genericv8_sys_regs[] = {
- { SYS_DESC(SYS_ACTLR_EL1), access_actlr, reset_actlr, ACTLR_EL1 },
+ { SYS_DESC(SYS_ACTLR_EL1), access_actlr, },
};
static const struct sys_reg_desc genericv8_cp15_regs[] = {
/* ACTLR */
- { Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b001),
- access_actlr },
+ { Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b001), access_actlr },
+ { Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b011), access_actlr },
};
static struct kvm_sys_reg_target_table genericv8_target_table = {
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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