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Extend x2APIC check as per VT-d specification

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mintsuki 2020-10-12 21:20:58 +02:00
parent c778e72af8
commit 513d0a2279
3 changed files with 71 additions and 41 deletions
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stage2/sys/lapic.c Normal file
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#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include <sys/lapic.h>
#include <sys/cpu.h>
#include <lib/blib.h>
#include <lib/acpi.h>
struct dmar {
struct sdt;
uint8_t host_address_width;
uint8_t flags;
uint8_t reserved[10];
symbol remapping_structures;
} __attribute__((packed));
uint32_t lapic_read(uint32_t reg) {
size_t lapic_mmio_base = (size_t)(rdmsr(0x1b) & 0xfffff000);
return mmind((void *)(lapic_mmio_base + reg));
}
void lapic_write(uint32_t reg, uint32_t data) {
size_t lapic_mmio_base = (size_t)(rdmsr(0x1b) & 0xfffff000);
mmoutd((void *)(lapic_mmio_base + reg), data);
}
bool x2apic_check(void) {
uint32_t eax, ebx, ecx, edx;
cpuid(1, 0, &eax, &ebx, &ecx, &edx);
if (!(ecx & (1 << 21)))
return false;
// According to the Intel VT-d spec, we're required
// to check if bit 0 and 1 of the flags field of the
// DMAR ACPI table are set, and if they are, we should
// not report x2APIC capabilities.
struct dmar *dmar = acpi_get_table("DMAR", 0);
if (!dmar)
return true;
if ((dmar->flags & (1 << 0)) && (dmar->flags & (1 << 1)))
return false;
return true;
}
bool x2apic_enable(void) {
if (!x2apic_check())
return false;
uint64_t ia32_apic_base = rdmsr(0x1b);
ia32_apic_base |= (1 << 10);
wrmsr(0x1b, ia32_apic_base);
return true;
}
uint64_t x2apic_read(uint32_t reg) {
return rdmsr(0x800 + (reg >> 4));
}
void x2apic_write(uint32_t reg, uint64_t data) {
wrmsr(0x800 + (reg >> 4), data);
}

47
stage2/sys/lapic.h
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#define __SYS__APIC_H__ #define __SYS__APIC_H__
#include <stdint.h> #include <stdint.h>
#include <stddef.h>
#include <stdbool.h> #include <stdbool.h>
#include <sys/cpu.h>
#include <lib/blib.h>
#define LAPIC_REG_ICR0 0x300 #define LAPIC_REG_ICR0 0x300
#define LAPIC_REG_ICR1 0x310 #define LAPIC_REG_ICR1 0x310
#define LAPIC_REG_SPURIOUS 0x0f0 #define LAPIC_REG_SPURIOUS 0x0f0
#define LAPIC_REG_EOI 0x0b0 #define LAPIC_REG_EOI 0x0b0
static inline uint32_t lapic_read(uint32_t reg) { uint32_t lapic_read(uint32_t reg);
size_t lapic_mmio_base = (size_t)(rdmsr(0x1b) & 0xfffff000); void lapic_write(uint32_t reg, uint32_t data);
return mmind((void *)(lapic_mmio_base + reg)); bool x2apic_check(void);
} bool x2apic_enable(void);
uint64_t x2apic_read(uint32_t reg);
static inline void lapic_write(uint32_t reg, uint32_t data) { void x2apic_write(uint32_t reg, uint64_t data);
size_t lapic_mmio_base = (size_t)(rdmsr(0x1b) & 0xfffff000);
mmoutd((void *)(lapic_mmio_base + reg), data);
}
static inline bool x2apic_check(void) {
uint32_t eax, ebx, ecx, edx;
cpuid(1, 0, &eax, &ebx, &ecx, &edx);
if (!(ecx & (1 << 21)))
return false;
return true;
}
static inline bool x2apic_enable(void) {
if (!x2apic_check())
return false;
uint64_t ia32_apic_base = rdmsr(0x1b);
ia32_apic_base |= (1 << 10);
wrmsr(0x1b, ia32_apic_base);
return true;
}
static inline uint64_t x2apic_read(uint32_t reg) {
return rdmsr(0x800 + (reg >> 4));
}
static inline void x2apic_write(uint32_t reg, uint64_t data) {
wrmsr(0x800 + (reg >> 4), data);
}
#endif #endif