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ANDROID: KVM: arm64: Reprogram S2MPUs in 'host_smc_handler'

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Intercept SMCs known to be used by the host to inform EL3 about power
events, either powering SoC blocks on or off.

Test: builds, boots
Bug: 190463801
Signed-off-by: David Brazdil <dbrazdil@google.com>
Change-Id: I936f7aaecf3ec77ec252f067a3c1571aadba4cdb
This commit is contained in:
David Brazdil
2021-06-29 17:15:17 +00:00
parent 8aa6c440da
commit 8ca0b34fe4
1 changed files with 76 additions and 0 deletions
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76
arch/arm64/kvm/hyp/nvhe/iommu/s2mpu.c
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@@ -11,7 +11,14 @@
#include <asm/kvm_mmu.h>
#include <asm/kvm_s2mpu.h>
#include <linux/arm-smccc.h>
#include <nvhe/mm.h>
#include <nvhe/spinlock.h>
#include <nvhe/trap_handler.h>
#define SMC_CMD_PREPARE_PD_ONOFF 0x82000410
#define SMC_MODE_POWER_UP 1
#define for_each_s2mpu(i) \
for ((i) = &kvm_hyp_s2mpus[0]; (i) != &kvm_hyp_s2mpus[kvm_hyp_nr_s2mpus]; (i)++)
@@ -22,6 +29,8 @@
size_t __ro_after_init kvm_hyp_nr_s2mpus;
struct s2mpu __ro_after_init *kvm_hyp_s2mpus;
static hyp_spinlock_t s2mpu_lock;
static bool is_version(struct s2mpu *dev, u32 version)
{
return (dev->version & VERSION_CHECK_MASK) == version;
@@ -40,6 +49,19 @@ static bool is_powered_on(struct s2mpu *dev)
}
}
static bool is_in_power_domain(struct s2mpu *dev, u64 power_domain_id)
{
switch (dev->power_state) {
case S2MPU_POWER_ALWAYS_ON:
return false;
case S2MPU_POWER_ON:
case S2MPU_POWER_OFF:
return dev->power_domain_id == power_domain_id;
default:
BUG();
}
}
/*
* Write CONTEXT_CFG_VALID_VID configuration before touching L1ENTRY* registers.
* Writes to those registers are ignored unless there is a context ID allocated
@@ -119,6 +141,59 @@ static void initialize_with_prot(struct s2mpu *dev, enum mpt_prot prot)
__set_control_regs(dev);
}
static bool s2mpu_host_smc_handler(struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(u64, fn, host_ctxt, 0);
DECLARE_REG(u64, mode, host_ctxt, 1);
DECLARE_REG(u64, domain_id, host_ctxt, 2);
DECLARE_REG(u64, group, host_ctxt, 3);
struct arm_smccc_res res;
struct s2mpu *dev;
if (fn != SMC_CMD_PREPARE_PD_ONOFF)
return false; /* SMC not handled */
/*
* Host is notifying EL3 that a power domain was turned on/off.
* Use this SMC as a trigger to program the S2MPUs.
* Note that the host may be malicious and issue this SMC arbitrarily.
*
* Power on:
* It is paramount that the S2MPU reset state is enabled and blocking
* all traffic. That way the host is forced to issue a power-on SMC to
* unblock the S2MPUs.
*
* Power down:
* A power-down SMC is a hint for hyp to stop updating the S2MPU, lest
* writes to powered-down MMIO registers produce SErrors in the host.
* However, hyp must perform one last update - putting the S2MPUs back
* to their blocking reset state - in case the host does not actually
* power them down and continues issuing DMA traffic.
*/
hyp_spin_lock(&s2mpu_lock);
arm_smccc_1_1_smc(fn, mode, domain_id, group, &res);
if (res.a0 == SMCCC_RET_SUCCESS) {
for_each_s2mpu(dev) {
if (!is_in_power_domain(dev, domain_id))
continue;
if (mode == SMC_MODE_POWER_UP) {
dev->power_state = S2MPU_POWER_ON;
initialize_with_prot(dev, MPT_PROT_RW);
} else {
initialize_with_prot(dev, MPT_PROT_NONE);
dev->power_state = S2MPU_POWER_OFF;
}
}
}
hyp_spin_unlock(&s2mpu_lock);
cpu_reg(host_ctxt, 0) = res.a0;
return true; /* SMC handled */
}
static int s2mpu_init(void)
{
struct s2mpu *dev;
@@ -150,4 +225,5 @@ static int s2mpu_init(void)
const struct kvm_iommu_ops kvm_s2mpu_ops = (struct kvm_iommu_ops){
.init = s2mpu_init,
.host_smc_handler = s2mpu_host_smc_handler,
};