MFC 261504:

Add support for FreeBSD/i386 guests under bhyve.

2 files changed, 167 insertions, 2 deletions

diff --git a/lib/libvmmapi/vmmapi.h b/lib/libvmmapi/vmmapi.h
index 8428987..4a3db5d 100644
--- a/lib/libvmmapi/vmmapi.h
+++ b/lib/libvmmapi/vmmapi.h
@@ -111,5 +111,8 @@ int	vcpu_reset(struct vmctx *ctx, int vcpu);
 int	vm_setup_freebsd_registers(struct vmctx *ctx, int vcpu,
 				uint64_t rip, uint64_t cr3, uint64_t gdtbase,
 				uint64_t rsp);
+int	vm_setup_freebsd_registers_i386(struct vmctx *vmctx, int vcpu,
+					uint32_t eip, uint32_t gdtbase,
+					uint32_t esp);
 void	vm_setup_freebsd_gdt(uint64_t *gdtr);
 #endif	/* _VMMAPI_H_ */
diff --git a/lib/libvmmapi/vmmapi_freebsd.c b/lib/libvmmapi/vmmapi_freebsd.c
index 9bd2988..d801184 100644
--- a/lib/libvmmapi/vmmapi_freebsd.c
+++ b/lib/libvmmapi/vmmapi_freebsd.c
@@ -35,14 +35,176 @@ __FBSDID("$FreeBSD$");
 #include <machine/segments.h>
 #include <machine/vmm.h>
 
+#include <errno.h>
+#include <string.h>
+
 #include "vmmapi.h"
 
+#define	I386_TSS_SIZE		104
+
+#define	DESC_PRESENT		0x00000080
+#define	DESC_LONGMODE		0x00002000
+#define	DESC_DEF32		0x00004000
+#define	DESC_GRAN		0x00008000
 #define	DESC_UNUSABLE		0x00010000
 
 #define	GUEST_NULL_SEL		0
 #define	GUEST_CODE_SEL		1
 #define	GUEST_DATA_SEL		2
-#define	GUEST_GDTR_LIMIT	(3 * 8 - 1)
+#define	GUEST_TSS_SEL		3
+#define	GUEST_GDTR_LIMIT64	(3 * 8 - 1)
+
+static struct segment_descriptor i386_gdt[] = {
+	{},						/* NULL */
+	{ .sd_lolimit = 0xffff, .sd_type = SDT_MEMER,	/* CODE */
+	  .sd_p = 1, .sd_hilimit = 0xf, .sd_def32 = 1, .sd_gran = 1 }, 
+	{ .sd_lolimit = 0xffff, .sd_type = SDT_MEMRW,	/* DATA */
+	  .sd_p = 1, .sd_hilimit = 0xf, .sd_def32 = 1, .sd_gran = 1 },
+	{ .sd_lolimit = I386_TSS_SIZE - 1,		/* TSS */
+	  .sd_type = SDT_SYS386TSS, .sd_p = 1 }
+};
+
+/*
+ * Setup the 'vcpu' register set such that it will begin execution at
+ * 'eip' in flat mode.
+ */
+int
+vm_setup_freebsd_registers_i386(struct vmctx *vmctx, int vcpu, uint32_t eip,
+				uint32_t gdtbase, uint32_t esp)
+{
+	uint64_t cr0, rflags, desc_base;
+	uint32_t desc_access, desc_limit, tssbase;
+	uint16_t gsel;
+	struct segment_descriptor *gdt;
+	int error, tmp;
+
+	/* A 32-bit guest requires unrestricted mode. */	
+	error = vm_get_capability(vmctx, vcpu, VM_CAP_UNRESTRICTED_GUEST, &tmp);
+	if (error)
+		goto done;
+	error = vm_set_capability(vmctx, vcpu, VM_CAP_UNRESTRICTED_GUEST, 1);
+	if (error)
+		goto done;
+
+	cr0 = CR0_PE | CR0_NE;
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_CR0, cr0)) != 0)
+		goto done;
+
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_CR4, 0)) != 0)
+		goto done;
+
+	/*
+	 * Forcing EFER to 0 causes bhyve to clear the "IA-32e guest
+	 * mode" entry control.
+	 */
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_EFER, 0)))
+		goto done;
+
+	gdt = vm_map_gpa(vmctx, gdtbase, 0x1000);
+	if (gdt == NULL)
+		return (EFAULT);
+	memcpy(gdt, i386_gdt, sizeof(i386_gdt));
+	desc_base = gdtbase;
+	desc_limit = sizeof(i386_gdt) - 1;
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_GDTR,
+			    desc_base, desc_limit, 0);
+	if (error != 0)
+		goto done;
+
+	/* Place the TSS one page above the GDT. */
+	tssbase = gdtbase + 0x1000;
+	gdt[3].sd_lobase = tssbase;	
+
+	rflags = 0x2;
+	error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_RFLAGS, rflags);
+	if (error)
+		goto done;
+
+	desc_base = 0;
+	desc_limit = 0xffffffff;
+	desc_access = DESC_GRAN | DESC_DEF32 | DESC_PRESENT | SDT_MEMERA;
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_CS,
+			    desc_base, desc_limit, desc_access);
+
+	desc_access = DESC_GRAN | DESC_DEF32 | DESC_PRESENT | SDT_MEMRWA;
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_DS,
+			    desc_base, desc_limit, desc_access);
+	if (error)
+		goto done;
+
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_ES,
+			    desc_base, desc_limit, desc_access);
+	if (error)
+		goto done;
+
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_FS,
+			    desc_base, desc_limit, desc_access);
+	if (error)
+		goto done;
+
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_GS,
+			    desc_base, desc_limit, desc_access);
+	if (error)
+		goto done;
+
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_SS,
+			    desc_base, desc_limit, desc_access);
+	if (error)
+		goto done;
+
+	desc_base = tssbase;
+	desc_limit = I386_TSS_SIZE - 1;
+	desc_access = DESC_PRESENT | SDT_SYS386BSY;
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_TR,
+			    desc_base, desc_limit, desc_access);
+	if (error)
+		goto done;
+
+	
+	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_LDTR, 0, 0,
+			    DESC_UNUSABLE);
+	if (error)
+		goto done;
+
+	gsel = GSEL(GUEST_CODE_SEL, SEL_KPL);
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_CS, gsel)) != 0)
+		goto done;
+	
+	gsel = GSEL(GUEST_DATA_SEL, SEL_KPL);
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_DS, gsel)) != 0)
+		goto done;
+	
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_ES, gsel)) != 0)
+		goto done;
+
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_FS, gsel)) != 0)
+		goto done;
+	
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_GS, gsel)) != 0)
+		goto done;
+	
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_SS, gsel)) != 0)
+		goto done;
+
+	gsel = GSEL(GUEST_TSS_SEL, SEL_KPL);
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_TR, gsel)) != 0)
+		goto done;
+
+	/* LDTR is pointing to the null selector */
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_LDTR, 0)) != 0)
+		goto done;
+
+	/* entry point */
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_RIP, eip)) != 0)
+		goto done;
+
+	if ((error = vm_set_register(vmctx, vcpu, VM_REG_GUEST_RSP, esp)) != 0)
+		goto done;
+
+	error = 0;
+done:
+	return (error);
+}
 
 void     
 vm_setup_freebsd_gdt(uint64_t *gdtr)
@@ -168,7 +330,7 @@ vm_setup_freebsd_registers(struct vmctx *vmctx, int vcpu,
 		goto done;
 
 	desc_base = gdtbase;
-	desc_limit = GUEST_GDTR_LIMIT;
+	desc_limit = GUEST_GDTR_LIMIT64;
 	error = vm_set_desc(vmctx, vcpu, VM_REG_GUEST_GDTR,
 			    desc_base, desc_limit, 0);
 	if (error != 0)